Until a few months ago I lead part of the XLA team at Google, working on ML compilers for CPU/GPU.
Most of us didn't have 10+ years of experience in compilers when we started on the team. I know one of us had a PhD in compilers. Possibly others did too, I'm not sure; this goes to show how unimportant the PhD in compilers / PhD at all was. I had no experience in compilers before I joined (not as the lead).
We're unusual, but I want to demonstrate that you really can get a good job working on compilers without a PhD or 10+ years of experience.
A PhD can get your foot in the door (showing mastery via the research you’ve done vs work experience). And then either/or is very useful in even knowing about and being recommended for these jobs (HR is generally not very useful in hiring).
PL isn’t really a hot area ATM, including implementation. Even formal verification jobs are a bit hard to find these days. Perhaps it will be more popular when the next AI winter comes around :).