For the reasons you are stating the snapshot is actually a boon. More than I’d like to admit I’ve had to write something that has been done so many times before with some slight structural differences. And of course there isn’t a library flexible enough nor enough time to write that library. Instead of just busywork mindlessly writing something that should just exist already. You can just slop it out quickly then spend the time it would have taken to write that, to refine it into something maintainable with all the new changes that are actually interesting and useful improvements. I see it as raising the bar of starting point.
That said, I just license my own stuff as MIT because I want to raise the bar for everyone, though I know it’s likely the AI companies haven’t respected the wishes of those who don’t do/want that.
I’d be interested to know where you draw the line of code ownership. Arguably FOSS is the place where projects are most likely to become a Ship of Theseus.
From my perspective AI slop is pretty unusable as it comes out, but can be an approximate starting point. It seems generous to call an LLM a coauthor, I’d be more likely to have a long list of Stack Overflow commenters as coauthors first.