The early successes he had made him overconfident. I don't see the formulas he displays as anything sort of revolutionary.
Any computer game today have systems way more sophisticated than that, or even old systems like the "sims" engine(original CimCity, Spore), Civilization series, doom, mafia, a flight simulator or Age of Empires to name a few. All those systems have incredible internal mathematical models.
He risked anything he had on his vision. His vision came sort. He does not accept reality. Even today he believes his visions are right and the world is wrong.
The "I blew it" is not acceptance of his failures. It is an acceptance of the failures of society that was not prepared for his revolutionary ideas. Society was not yet prepared for his genius. He made the mistake of valuing society more than what is worth.