I'd argue this has been happening for years and years now. If you want a pithy saying, you could say that over time languages become closer and closer to Haskell.
Option types, pattern matching, pure functions (see: Vue/React with computed properties, or any other frameworks doing things close to functional reactive programming), type inference (even Java is getting a var keyword!), more powerful type systems (things like the Typescripts of the world have) are now becoming trendy, but Haskell had them years and years ago.
The above is definitely oversimplifying (a short HN comment is no place to get into the fundamentals behind the various kinds of type systems), but I've found all the things I love in Haskell and other FP languages seem to slowly drift on over to other languages, albeit often a little suckier.
(I'm still waiting on software transactional memory to become mainstream, though. Of course, in languages that allow mutable state and without some way to specify a function has side effects, you're never gonna get quite as nice as Haskell. Oh well.)
That's a statement worthy of highlighting, supported by examples below it. I'll remember that as I continue to study more languages.
As it turns out, Python continues to be one of the top three languages in terms of popularity. It's not clear if this has helped feed a bigger userbase into purist FP languages though.
People are generally more willing to accept incremental changes than an entirely new way of doing things. For good reasons: they're skeptical, availability of talent, tools, libraries, IDEs, help if they run into trouble...
An analogy is the spread of yoga in the west the past decade or two, because it was easy to do so without changing your lifestyle. If Westerners were asked to fly to the Himalayas for a month to learn yoga, how many would have learnt yoga?