"The TIOBE index measures how many Internet pages exist for a particular programming language."
For some reason I doubt this is in any way representative of the real world. Scratch, which is a teaching language for children, bigger than PHP? Which is smaller than Rust? Yeah, these are results you get when you look at the Internet, alright.
Sure that index isn't great (I think it's basically a regurgitation of Google Trends), but I don't think you're suggesting Clojure is actually a popular language are you? Which is the only point I'm trying to make (that it isn't popular).