Yup, I have been a junior compiler engineer at three(!) different jobs early in my career, before moving on to other stuff.

It has never been a huge niche. It's fun work if you can get it. There were often MIT grads around, but I don't think it made you an automatic hire?

Once in a blue moon, for old times' sake, I send a bug fix PR for someone's optimizer, or build a small transpiler for something.