Very much a personal anecdote, but I spent about a month earlier this year seriously learning various Lisps (CL, Racket Scheme, Clojure). I stopped when it clicked for me - Lisps are a mess. Everything I wanted from Lisp I found in Haskell.

I'm reasonably confident that all the anecdotes you hear about 10x improvements from switching to Lisp are just programmers learning about functional programming and good design patterns for the first time. But those aren't contingent on using a Lisp, and I'd argue using Lisp brings an enormous amount of cruft and baggage that makes FP seem far more alien and difficult than it needs to be.