Definitely not as some grim prognosis of AI ruling or something like that. More in a sense of seeing many of these startups popping up to take advantage of the AI hype, although most of theme being quite late to the party. And market traditionally overestimating the potential of AI an the crash that will follow.
One possible way it could end badly would be if OpenAI ramped it's pricing up to the point where it takes away most of those company's chances of ever being profitable.
I'm not saying it's going to happen, and I hope it doesn't, but when I did a little analysis for an idea I have it was absolutely the biggest threat I could see. OpenAI has the ultimate vendor lock-in - there literally isn't an alternative right now.
(This is a giant opportunity if you're a billionaire investor. Providing an AI backend is probably the next cloud infrastructure. OpenAI is going to be the AWS of that industry, but there's room for an Azure or a GCP too.)
There's really no point in worrying about OpenAI shutting down their API or pricing you out. It may happen but very unlikely that it will be suddenly and soon.
Yes, keep it in the back of your mind and design your systems in such way that when the time comes replacing the GPT doesn't require rewriting your entire codebase.
Your immediate #1 priority in such competitive market should be to execute your idea and get paying customers, then you deal with breaking off OpenAI.