I think that there is a bubble but it's shaped more like the web bubble and less like the crypto bubble.
Regarding LLMs there are two concerns - current products don't have any killer feature to lock in customers, so people can easily jump ship. And diminishing returns, if there won't be a clear progress with models, then free/small, maybe even local models will fill most of people needs.
People are speculating that even OAI is burning more money than they make, it's hard to say what will happen if customer churn will increase. Like for example me - I never paid for LLMs specifically, and didn't use them in any major way, but I used free Claude for testing how it works, maybe incorporating in the workflow. I may transitioned to the paid tier in the future. But recently someone noted that Google cloud storage includes "free" Gemini Pro and I've switched to it, because why not, I'm already paying for the storage part. And there was nothing keeping me with Anthropic. Actually that name alone is revolting imo. I wrote this as an example that when monsters like Google or Microsoft or Apple would start bundling their solutions (and advertise them properly, unlike Google), then specialized companies including OAI will feel very very bad, with their insane expenses and investments.