A great point. Since it's built on top of the erlang VM, and it has all the cool tools built into the eralng VM and OTP, Elixir has been able to rapidly go from a prototype language to a production grade environment to work in extremely quickly.

But also to basically decide that the language ergonomics and syntax is "finished" this quickly is truly impressive. The addition of macros, combined with the huge focus on developer experience, I think allows the core team to say "its feature complete" while not worrying about any particular missing features in the language (you can probably just implement it yourself anyway)