If you like writing Ruby on Rails, then good, keep doing it. People are. I believe it still works. What's the big deal?
Obviously, people use JavaScript (whether with React, or with another framework, or without any framework), deploy micro-services, use Kubernetes, etc., with their Rails applications, so I'm not quite sure what you're trying to say with that part.
> what is the inevitable of rubists and rails folk?
Eventually they will all die that one seems inevitable
AI writing code has zilch to do with anything, as no piece of non-trivial business software can currently be written by AI.
None of the new frameworks developed in the past 10 years do anything to improve developer productivity over what people already have with Django, Rails, and Laravel.
We're a fad-driven industry and most people can't tell productive work from their ass.