I haven't had a serious look at it yet, but the Ruby/Rails ecosystem is really big. I'd bet Elixir isn't quite there yet. I like what I've seen so far, though.

I'd argue that in the vast majority of cases, anything 'missing' from the ecosystem is probably one of those gems that probably shouldn't be a project dependency anyway. That doesn't mean it won't filter its way over to the Elixir ecosystem at some point, but I don't think you'll find any of the major pieces missing.