This is probably acting as a proxy for growth in programming jobs and IT in general.
Just about every programming language looks like baseline noise compared to Java. Still, there's no denying these are both still very much niche languages.
As is functional programming in general. But it's growing.
I've been hacking around on the side in functional languages for over ten years now and I don't ever remember seeing close to this much mainstream interest in functional languages. The web opened the door for anything that can talk HTTP and Python and Ruby made FP seem a lot less exotic.