Hi Joel, thanks for your post. A few points though:
Can you name one pure functional language which gained wide popularity and success?
Sure, there’s actually a bunch, but here’s a few interesting ones: haskell, Scala, Elixir, Lisp, elm, Cycle.js, F#, LINQ, ClojureScript, ReactiveX, etc.
Scala is not a pure functional language. The OOP features are obviously not, and the FP ones are not either (you can write side-effects everywhere in your functional code, nothing forces you -yet- to be explicit).
Some other languages that you mention, such as Elixir, Lisp or Elm, even Clojure, are minority. I wouldn’t say they’ve been a success, even if some of them are becoming more used.
A language being functional or non-functional, has no impact on structure or code organization.
Of course it has an impact on structure. Have you seen the different ways of writing code in, let’s say, Scala? The code written in OOP is completely different structured compared to FP.