He has. He’s notably been burned a few times, one of the worst of which was 2021
TSLA. Iirc he was early but not wrong, with the 2022 collapse of all things ARKK related crashing and burning.
He's been bearish for the last n years. His Twitter handle is Cassandra because he tries to warn people about impending doom, but nobody listens. He gave up at one point because he tweeted SELL and then everything was fine.
tl;dr he's a perma bear.
I actually don't think he's wrong, but one thing I've learned is that it's not enough to recognize a bubble. Almost everyone sees the markets are, as they say, frothy. But you need to see if there's a needle nearby. Without that you're just trying to get lucky.
Puts especially are really hard because they expire. They limit your loss compared to shorts, but you need to time it perfectly.