Having been a rails engineer for 12+ years, I can say I haven't used rails for front end work in about 5 years. In 2011 I started migrating front ends from erb to ERB heavily enhanced with angular, my frontends relied more and more on an API and slowly, the "@" instance variable assigment started to disappear from my controllers.

I'd say many shops have had a similar experience, and full stack development no longer depends on rails for frontend. Which means that the only rails jobs out there, are likely backend/API/distributed systems.

There was a time when I thought rails was out the door and node.js was in, and I converted several large rails codebases over to node.js/express. Looking back, I don't think the node.js community was strong enough, and even today I still miss Ruby's debugging ecosystem.

I once sat down to write a medium post a few years back on why rails is still the best choice for backends. I would cite the number of packages for sidekiq, the diversity of email handling libraries, and the multitude of packages to handle just about everything. I compared it to rust, and go. The only problem was, any time I tried to say "rails has this, X doesn't" Go had X.

Rails will stick around, but I'd recommend smart engineers diversify. Study modern node.js codebases (things have gotten much more manageable with await/async). Study Go. Also, check out actioncable, and start a new rails project with "rails new --webpack=react" and build something. Seems the rails team has embraced the modern world, which may make it one of the best cohesive ecosystems right now.