I agree that Elixir & Phoenix are the natural evolution in a post-Rails world, but looking further ahead, I think we've reached a point where the compiled & typed languages are starting to have all the goodies that used to be reserved only for the highest of the high level languages, and with web assembly support on the rise, it's going to start to become possible to use languages like this for both backend and frontend in a unified way. So for me, the next natural evolution is using something like Rust or Crystal but with very solid Railsy conventions and intelligent code sharing between frontend and backend. I think this combined with something like the Phoenix live view, but in Rust, is at least where I want my future to be, and I think a workflow like this could become the dominant pattern before, say, Elixir/Phoenix overtakes Rails.

I tip my hat though to people diving into Elixir --- it is definitely a cool direction and one I would follow if I weren't already so sold on Rust/Crystal/etc.