I can’t say really, but my recollection is that the last decade of higher interest in FP has had Haskell as a fixture, and was significantly sparked by the need to program in a multi core world, and parallelization is made significantly simpler in the context of pure FP and controlled side effects.

I hear you though. I was mostly a lisp person and only really got into Haskell in the last couple of years. Even still I would have said that the FP zeitgeist had Haskell as it’s central example of FP.