>> I'm surprised it has not been adopted by that many folks in production.
I'm surprised that it's used in production at all. It's based on a new language that is years behind all the others in terms of available third-party libraries and modules.
Does the language lack some maturity? Sure. But you don't have to use pure elixir for everything. You can leverage most Erlang packages. Phoenix is hosted on Cowboy[0] which is a mature, battle tested web server written in Erlang.
I'm surprised that it's used in production at all. It's based on a new language that is years behind all the others in terms of available third-party libraries and modules.