Eh, he had made exactly these sorts of bets before and he won those. Because it is gambling, eventually you lose a bet or two. While experienced gamblers learn to manage risk- mostly by diversifying and betting small chunks of your pot on different, uncorrelated bets, SBF never did. He continually bet his entire net worth- and his freedom- in one big gamble again and again. And it worked for a while. Until it didn't. But if he did get this bet to pay off, then he would have done it again, clearly. And eventually, one of the gambles would break like this one did.