The most recent StackOverflow poll shows Elixir as having the highest percentage of people happy with working with it (over 70%), taking top spots among all tech languages and platforms … and is among the lowest for tech people wish they are using for work, but are not.
In other words, many of the developers who want to be working with Elixir are working with Elixir, and are quite happy doing so.
Maybe there are better metrics to gage momentum.