I've been thinking that there might not be new programming languages. The amount of code in the current popular ones will explode, so that's what all LLMs will be trained on.
Good luck coming up with a new language and getting enough content out there that LLMs will be fluent with it.
If true, I think that's a shame. There's plenty of innovation still to be done.
How pessimistic you are on this subject depends on how much you believe in domain transfer for these tools. No programming language sprung out of a vacuum, and it seems reasonable to think that a LLM sufficiently trained on all the C++, Haskell, and OCaml in the world could probably do a decent job at writing Rust, even if it had never seen it before, given the rust compiler as a tool and rust documentation as input
It certainly does worry me, though. As does the increasing amount of materials and manuals that seem to be written assuming the LLMs will be the (only? primary?) audience