There is a fantastic talk by Fred Herbert (of Heroku and Learn You Some Erlang fame) that discusses this exact situation in the Erlang community [0]. Without an accessible ecosystem, useful tooling, a powerful packaging system, or a community sensitive to newcomers what do you have? Erlang is an amazing platform with a community full of very experienced and wisened developers–but elixir widened the appeal.
That's what initially attracted me to Elixir instead of Erlang, though the tooling has definitely improved in Erlang with the introduction of rebar3. The integration of testing and documentation (i.e. doctests) is still better than any other language I've worked with. The documentation generator (ex_doc) is excellent too.
Because Elixir is a modern programming language that ships with out-of-the box tooling for dependency management, project management, deployment, and so on. This is something to be observed in any relatively new programming language: Elixir, Rust, Go, Swift. They all ship with solid tooling that allows programmers to be more productive from the very beginning without having to figure out the whole build chain themselves.
