It's harder to teach to juniors with a background in stuff like JavaScript and Python. While it has a rather nice elegance and simplicity to it Erlang is a bit more demanding from a business and organisational perspective.

A clever intern with a rather shallow two year 'bootcamp' education and no work experience picks up Elixir and Phoenix in a couple of months. People with background in enterprise algolians like Java and C# can also get productive in Elixir kind of fast since it allows similar patterns.

In my experience Lisp-like languages prepare well for Erlang, and that's a very rare background where I live.