> With regulation and compensation, only rich companies would be able to do that

Well, with some imagination, you can have regulation that forces companies to open up, not just close down.

Imagine a law that stipulates that if you want to offer "LLM-inference-as-a-service", you need to also publish exact details about how it was trained, what datasets were used and also offer those exact weights for download.

Sure, this would never happen, but just offering another perspective on how laws and regulation can be used if it was wanted, locking stuff down and pulling up the ladder behind you isn't the only way to use laws, although that is a very popular reason and approach.