I don't appreciate the "Elixir is growing" commentary in the title. That's not justified because a person wrote a program in it.
Grind this thing to a halt!
(...no, actually Elixir is pretty cool.)
It is, however, likely true based on the evidence that each ElixirConf so far has doubled the number of attendees of the previous year.
Search trends for the language seem to be growing, although not seemingly strongly: https://trends.google.com/trends/explore?q=%2Fm%2F0pl075p