By skyforbes 
Petersen claims that the "lowest estimate we & Microsoft had for the game's total income was $1.1 billion," which is a staggering sum for any game to pull in. For context, Deadline reported in 2021 that the entire Halo franchise had reached 81 million copies sold at the time. Back of the napkin math at $60 a copy puts the series' revenue from game sales at around $5 billion after 20 years of existence.
While possibly a typo, Petersen's note that Titan started development in 2008 doesn't line up with prior accounts of the game's development which have the project starting in 2004 and getting canceled in mid-2007, around Don Mattrick's July, 2007 ascension as head of Xbox.
"It was all brought to naught when Don Mattrick realized that his stock bonus was based on the income MS had from games in three years," said Petersen. "You see, we estimated [three and a half] years to finish Titan if we did it right. And that’s beyond Mattrick’s drop dead date. So by firing ALL of Ensemble, he didn’t have to pay for our expensive studio for three years and he didn’t care about Titan.