I had this problem recently trying to hire people good at and willing to work with a big Angular v1 codebase.

Rendering programmers in video games industry. The problem is that any rendering programmers are immediately hoovered up by medical/automotive/research industries at ridiculous salaries that very few gaming companies can compete with, and even then there are very very few programmers who are interested in that area.

Yes, the answer to the problem is "just offer more money" but that decision is way above my paygrade - I have to hire someone though, and the choice of candidates is very small.