My own personal experience as a CTO and startup investor: I haven't seen Ruby (or even met someone whose primary language is Ruby) in a long time.
I think it had a moment ~10 years ago when a lot of people started companies using Rails. Some of them still use it, most of them just went out of business.
It hasn't been big since then. It seemed to only ever have become popular in a fairly limited bubble of startups, especially in Silicon Valley.