A scary (if not particularly original) thought: If people become utterly reliant on LLMs and no longer embrace any new language etc for which there is insufficient LLM training, new languages etc will no longer continue to be created.

If languages stop being created, it will be because there won't be a need for them. That's not necessarily a bad thing.

Think of programming languages as you currently think of CPU ISAs. We only need so many of those. And at this point, machine-instruction architecture has diverged so far from traditional ISAs that it no longer gets called that. Instead of x86 and ARM and RISC-V we talk about PTX and SASS and RDNA. Or rather, hardly anyone talks about them, because the interesting stuff happens at a higher level of abstraction.

Possible, but I think unlikely. New languages already suffer this uphill battle because they don't yet have a community to do Q&A like entrenched languages; their support is the documentation, source code of implementations, and whatever dedicated userbase they have as a seed for future community. People are currently utterly reliant on community-based support like StackOverflow, and new languages continue to be born.