I think you're correct, I'll just point out that compilers are also chaotic today and it is often accepted. A small change to source program can lead to big change in performance. It's especially apparent in high-level and declarative languages - SQL or anything with GC.

With respect to performance that’s true. But I’ve probably spent thousands of hours in my career on performance issues caused by small SQL changes.

And LLM chaos is unimaginably worse. A single white space can result in a program that has zero overlap with the original.

They can guarantee that certain small changes won't create a big change in performance (provably, verified through tests, or trivially). An LLM can't.