This'll be a niche for a long, long time.
Games are generally carefully crafted to deliver a specific mechanical and/or narrative experience. A world populated by LLM/etc bots or content is one choice of what that experience might be, but it's not going to be a very satisfying one for many game designers -- especially given the current/near state of the technology. There will be games and experiments that explore it, for sure, but the vast majority of games just don't have any need for it.