Yeah, that’s basically why.
Back in its heyday, Ruby had two basic niches. The bigger one was Rails. Rails is still alive today, but after the move towards richer frontends a lot of the hype, and consequently the developers, followed that trend into the JS world. It’s obviously possible to have rich React frontends and Rails backends if you want to, but that isn’t quite what you got with “omakase” Rails.
The other niche was in devops tooling, e.g. Chef and Puppet. But that space moved towards containerization and all of that tooling, more or less, got written in Go.