And it's clear that you don't know how cryptocurrency is actually being used, so it's not a useful analogue to AI. Except to the point that you don't know how AI is being used either.
The things that LLMs are being used for are already justifying their expense, otherwise they wouldn't be used in the first place. There's no "bubble" to pop on the usage side of things where jobs have been replaced by it, AI isn'tgoingto"go away." It's possible that some of the big providers like OpenAI or Anthropic might go out of business or get bought out, that's always a risk for first movers in a field like this, but if they fail it will be because others have stepped up to provide those services even more cheaply.