That's a bit too naive. Propaganda, marketing for products, fake reviews, referral links (or just links to promote blogs/new sites) all make money indirectly. There absolutely is money to make in any popular social network and due to its architecture fediverse is potentially even more susceptible to it. Without a plan to address it, it is only a matter of time before it becomes an issue (unless it stays a niche small community forever but I am skeptical even those are free from bots and malicious actors)

we could just implement like, Anubis checksum per post. it would cost those llm people hundreds if not thousands.