Likeness is just one aspect of copyright. Another side entirely involves the protection of the innovative and production parts of the creation of the original training material. I.e. ChatGPT wouldn’t be possible without the work of hundreds of millions of writers writing things.
Not so different than compensating a course for providing you with their learning materials when you learn a new language.
It’s more of a “why do I keep Windows on my main machine and only use Linux for my servers?”
The answer is two-fold
a) most of my games and a (dwindling) amount of productivity software are windows based. I know things are improving… But the fact remains that I am still literally invested in some software that is only supported on Windows (that pile is shrinking).
b) there are a few everyday tasks that are still just too frustrating to be practical for non-technical people. For example, why in the fuck do I need to deal with user and mod permissions for files on an external harddrive? I get why for system files, but for media files on an external drive? It’s a level of pedantry I’m just not ready to deal with.