There is also an ego aspect to it. When people have done well they think it is all skill. Look at people who were really successful on crypto and now give financial advise as if they were an economist. Or go to a casino and talk to someone after they win big.

What they can gain is in the ego as well. Though I 100% agree, always follow the money. But never underestimate how often things are written with the purpose of saying "look how great I am, you should envy me."