That's a bit of an oversimplification. If you're OK with remote, it's not hard to find Elixir devs. You can also start with just one or two senior people, and for the rest hire people with web experience (or whatever else is useful) in other languages.

There was a company hiring lots of Elixir devs that actually hired straight from bootcamps - I forgot the name unfortunately, they had an interview on the Elixir blog or Adopting Elixir book or somewhere like that...

I don't necessarily disagree with that sentiment, but you can also attract very good developers when you don't avoid exotic languages.