Where do you think most companies get "professional programmers" from, exactly?
Julia's been designed and implemented by some very bright people, and it shows.
Grad students may be brilliant but that does not help give them any insight in to what makes a good ecosystem, toolchain, and feature set good.
More seriously: part of the problem does seem to be that Julia does have some significant differences from "traditional" languages (e.g. the concept of a "virtual method" is a bit fuzzy in Julia, what we call a JIT is probably better described as a JAOT, whether it has a "type system", homoiconicity, etc.).
That said, this JuliaCon I have met a lot more people from and classical "programmer" backgrounds. So hopefully that is changing.