Huh, maybe I just haven't been talking to the right people. I always felt like I was surrounded by people who didn't want to bother with functional languages any further.

It's true that every mainstream language has adopted first-class functions, but that's not all that a functional language gives you. Writing in Common Lisp or Scheme, you have to adapt a different outlook on how you view states, what a function means, what side-effects are, and you become very much more careful about how and when you apply those concepts in your programs.

But yeah, I agree with you, those concepts being included in mainstream languages definitely decreases the barrier to entry to more pure functional languages, and definitely pushed more people toward there.

Didn't think of Scala, you're right, it's very popular.

I was just speaking from personal experience, didn't actually look into how things are going outside my scope.