Can you say that about Standard ML? theres traditionally certain langs with particular ergonomics that lend them self to this kinda work. Like having (parser, lexer libs as apart of the lang's stdlib)
Rust's ADT seem particularly useful in this context. it really makes refactoring a breeze. (OCaml has a similar type system.)
What if you turn it around? "Most compiler engineers aren't Rubyists."
I don't know if that's true or not, but I imagine most compiler engineers tend to be more engrossed in languages like *ML, Rust, or Haskell. Or languages that are common in general, like C++ or Python. Ruby isn't that popular (outside of the Rails niche at least?), and it doesn't fit very well in a compiler niche either, I think.
But why would a compiler engineer that's not familiar with Ruby work on Ruby? They have so many other languages to choose from. I don't necessarily think that writing a JIT in Ruby is a good strategy to attract people to work on it, but if you are going to attract compiler people, you most likely want those who are also Rubyists.
Speaking mostly for myself, at least some compiler engineers like difficult source or target languages. The very dynamic ones are difficult to compile efficiently and thus more interesting than some alternatives. Plus Ruby hasn't had the attention paid to it that JavaScript has so the design space is closer to greenfield. I can see the attraction.
You could say that about any language.