He didn’t predict those games.

Not sure what criteria you are going for. He objectively was talking about HLX (codename for Alyx) and Neon Prime (early name for what became Deadlock) years before the respective games released.

watched footage from the leaked gameplays of people not holding the emargo

That’s shortly before release, at that point the game was not a secret anyway.

Of course none of this means he’s any better at guessing prices than anyone else.