GP isn't asking about the "endgame" as in "for what purpose did this author do this thing?". It was "endgame" as in "how is the story of LLMs going to end up?".
It could be "just" more cat and mouse, like you both mentioned. But a sibling comment talks about the possibility for architectural changes, and I'm reminded of a comment [1] from the other week by inawarminister ...
[1]: https://news.ycombinator.com/item?id=38123310
I think it would be very interesting to see something that works like an LLM but where instead of consuming and producing natural language, it operates on something like Clojure/EDN.