Judging just by these two videos, this junk is just so so stupid. How did he made his fortune?
In fairness, I personally don't think Cramer is stupid at all. In fact, I think he's highly intelligent.
First, as he said on other occasions, anyone whose main job is to call stock prices day in and day out is bound to make plenty of bad calls; it's just that he's the one shouting them on TV (and I really give him credit for that). To me, this only illustrates how neither intelligence, nor experience, track record, or even constantly being exposed to insiders and other highly informed people, can substitute for the ability to look at reality free of emotion and personal biases. I don't think he's stupid or malicious, but rather with as much experience as he has with the markets, it can become really difficult to step back and maintain a beginner's mind.
Second, to answer your question, he made his money by being a really good professional trader. Trading behind a real trading desk, backed by a real organization, is quite different, and he proved to be able to play that game quite well. While I think he doesn't hold a candle to say, Andrea James, when it comes to analyzing a new player that is changing the game, it's quite possible that Andrea couldn't compete with him as a trader.
Chanos, on the other hand, doesn't strike me as very bright at all. He's only an average, conventional thinker who got lucky.