So if you sell your crypto and make a profit in dollars, it’s exactly because a greater fool bought it at a higher price than you did. So every dollar that comes out of a cryptocurrency is because a later investor put a dollar in. They are inherently zero-sum by design, and when you take into account the casino (i.e. exchanges and miners) taking a rake on the game then the entire structure becomes strictly negative-sum. For every winner there are guaranteed to be multiple losers. It’s a game rigged by insiders by hacking human psychology.
www.stephendiehl.com/blog/against-crypto.html