If that was the case, why isn’t he playing with the big boys? If he was this good, he should be making millions and millions a year. Even if he doesn’t have the money, someone should be willing to sponsor him for millions or even tens of millions.

While no concrete evidence has been provided, there is a lot of statistical evidence (he’s on a practically impossible part of the bell curve), Occam’s Razor implies that he’s cheating. Moreover he only plays when twitch is rolling. The most likely explanation is that he’s giving a percentage of his winnings to some tech guy processing the feed, probably more than 50%.