By skyforbes 
Despite everything that has happened, Garaki and Flect have not actually been proven wrong. No, I don’t mean illegal experiments or the mass genocides, those were definitely wrong- I mean the very concept of the quirk singularity/doomsday theory hasn’t been disproven at all and is only getting reinforced.
Here’s a run down: the Paranormal singularity theory (later renamed the quirk doomsday theory) was a theory coined by Garaki around 7 decades before the start of the main series. The theory goes that, after every generation of quirk users, they have kids with other Individuals, causing 1 of 2 things to happen:
1. They have a child with another quirk holder, making their child have a fusion of their quirks, and thus make that child technically stronger than both of them.
2. They have a child with someone who is quirkless and their child just gets a copy of their quirk or an even stronger version of it.
Eventually this process will keep repeating endlessly, until eventually humanity won’t be able to handle the speed at which quirks get stronger and stronger. As time passes the way quirks work will become more complex with each generation. What if you had a parent who is a bear and one who’s a duck? Now the kid is a mix of the two. What if said kid has a child with someone who’s a fish and an insect? Now their child has a mix of all those traits- and so on. Or rather, what if your grand parents had fire and ice, and your other grand parents had lightening and wind?
Humanity naturally evolves to handle new issues, however quirks would evolve faster, so fast that human evolution wouldn’t be able to keep up- it would destroy their bodies from too much power, they might not even know how to use said power after how complicated the power has become to even understand let alone use.
The world proceed to say “That’s stupid” and destroyed Garaki’s home and the rest of his life. All for One picked him up from the bottom, being the only person to realise the doctors words had actual weight to them due to All for one letting him see the stronger quirks coming into existence through the passage of time, and the rest is history.
Now here’s the issue: he ended up being right. There are cases where two parents having a child had made that child much stronger than both combined (Shoto) or the opposite where the quirk actually hurts the child (Toya). However, the extreme cases of completely uncontrollable quirks have came in the last 2 generations and is now very much real.
The simplest, safest case is actually Toru Hagakure and her “Invisibility” quirk (Which should honestly be renamed to light refraction on the quirk registery at this point). Her quirk isn’t actually invisibility, but rather to refract all light around her body. While this is a nice quirk, there’s 1 issue; It’s turned on 24/7. She can’t turn it off. She couldn’t control her quirk at all, making her appear invisible to anyone who’d try looking at her for her entire life. She eventually learned that she could manipulate the light around her body, however even then all she could amuse it for was to blind people, she still couldn’t turn it off. Closest she had to turning it off was a simple thing no one had considered: forcing her quirk into exhausting. Her quirk is being used passively 24/7, but all quirks have limits. Whenever a laser made of light is shot at her, she redirect its cause by using her light refraction. When a strong enough amount of light is refracted by her it actually nearly turns her quirk off completely, showing more of her actual body (however it slowly turns back to normal anyways after the fact).
Well, Eri is the best example of this, but I want to talk about the less discussed examples that aren’t just “toddlers can’t possibly properly control their quirks if they’re too strong”.
Toru is the safest version of a quirk becoming uncontrollable and “hurting” the user. She’s the save side of this, however Flect turn is the extreme. His quirk reflect, like Hakagure is on 24/7. It’s the ability to reflect everything, even if the user doesn’t want. In fact, it even reflects all light from his body forcing Flect to be blind. The only reason he can see now is with the specially created support gear under his eyes stopping his quirk from reaching his eyes. Unlike Hakagure, Flects parents didn’t have his version of the quirk, but whatever they did have turned into his reflect quirk. For his entire life, Flect had never once felt a loving touch from his parents, from his friends, from those he loved, he literally couldn’t touch a single person without risk of injuring them or pushing them back from trying. He even attempted to end his own life, but even then his quirk stops the attempt. This is how he came to believe in the quirk doomsday theory, as he is a walking example of it. He eventually learned to control Reflect by having a bunch of support gear to compensate, however that’s a crutch that doesn’t actually deal with the real issue. Just like Hakagure, his quirk also has a limit, requiring a very laaaaarge amount of repeated force applied to his body to weaken reflect. After enough force is applied, the quirk is finally deactivated allowing him to have a normal life for a short amount of time until the quirk recovers, however he required dozens of one for all smashes on his body to achieve that, so it’s unlikely it will ever happen again.
Let’s pivot a bit. All we’ve been talking about are quirks that hurt the user by simply ruining their daily lives of just hindering their ability to have a life- what about quirks that hurt user due to how strong they are?
Nine is a wonderful example is Nine. His quirk, weather manipulation is god like. He can control all forms of weather- hurricanes, rain, lightening- this power makes him a true monster. However, there is an issue- the quirk is “too” powerful. So powerful, Nines body can’t properly handle it, it causes the destruction of Nine’s own cellular tissue with every use- even as he became a adult this never left, forcing him to use it soaringly, less it become fatal. This is the problem Garaki had realised. While users from the latest generation (the 5th/4th) naturally have stronger streamlined bodies for quirks in mind, they simply just can’t keep up. Nine’s body simply isn’t strong enough to use weather manipulation. The hardware just can’t handle the amount of information needed for the software, causing him to break apart.
Now, for the biggest contender of someone screwed over by quirk singularity is Anna Scervino. Her quirk, overmodification sounds great at first: If someone touches Her, their quirk gets completely altered and gain a massive boost, either in power or functionality. There is just 1- no wait, a lied. She has a lot of issues.
Overmodification, like Reflect or Invisibility is on 24/7, with Anna having no control over its activation. This doesn’t change her appearance in any ways, but it does cause multiple issues. Overmodification just like all quirks requires usage for the individuals mental well being, however unlike most quirks, it isn’t Anna’s mental well being in danger, it’s her physical well being. Overmodification if not used on a person long enough, activates on its own and immediately starts hurting Anna. If she doesn’t touch anyone and apply a successful overmodification she has a seizure and eventually blacks out. Ok, so logically as long as someone is with her, she can over modify them and she’s good, right?
Ha, ha, no no no, overmodification being on constantly isn’t the only handicap. It has a compatibility requirement. Whenever you touch Anna when overmodification is active, there is a chance you aren’t compatible with it, which means, that not only do you not get the quirk overmodified, but you also get knowcked out by a sudden jolt of pain just by touching Anna. Oh, what’s the chance of not being compatible? Oh, just a 2449 in 2500. Or rather, the chant of being compatible is 1/2500. Theres only a 0.0004% chance that you aren’t compatible with Anna, meaning there is around barely over 30,000 people on the planet who can be overmodified by her, meaning her options are ridiculously small in regards of ever using her quirk without hurting people or herself. Life for her is an actual living hell, barely living, with the only grace she has being she was born in a wealthy enough family to provide her needs. The only alternative to turning her quirk off forcibly with an erasure quirk like Aizawas.
The final thing I’m using is actually unique, and it’s about all for one. Theres see multiple reasons he needed Shigaraki’s body, but theres one that I don’t see a lot of people talk about: He needed his body to keep up with quirks. All for one is a first generation quirk user, from the very dawn of quirks. His body is actually the closest to the original human body as one can get… and that’s the problem. As time went on, people’s body evolved to handle stronger quirks. Each generation got stronger to deal with it: but All for one didn’t. His body is obsolete, as stronger and stronger quirks become more common, he wouldn’t be able to handle it himself. This is one of the reasons Shigaraki’s newer body is required, as Garaki explained. His hardware was the latest version, which would help all for one deal with the latest quirks easier physically is comparison.
Now that we know all this, with all this evidence, with multiple characters in universe claiming the theory is coming true and no one has been able to actually argue against it completely, even the heroes… what the heck do you do?
Nothing I guess. Eri is the latest example snd she’s barely 7. There is seemingly no actual solution to this. Flect turns idea was to basically eradicate very person with a quirk to save those left with quirks, but that wouldn’t work. People got quirks from nothing- the process will likely just repeat itself. Garaki seemingly didn’t really care about stopping quirk doomsday, he was busy just studying it and its effects. While he did gloat about being correct, he didn’t really see the need to actually stop the constant expansion.
So supposedly, other than dropping all morals killing every person on the planet (which would likely still not work, due to the fact even animals can gain quirks, though it’s much more Rae in comparison) their is seemingly no way to stop humanity from destroying itself in a few decays. One day, a baby will be born with a quirk that has it on fire constantly and they can never turn it off, or born with a quirk and said quirk will destroy the entire hospital upon activation, perhaps even destroying the baby within said hospital. The series never suggests any way to stop this (or even addresses it after season 7), and honestly? I can’t think of one either. This seems unavoidable like, bar erasing quirks which is impossible. The world is very much screwed.