I know that many of you will say Ruby is doing fine, etc... let me say that regarding jobs and adoption is not that great, especially compared to Python and a few others, without even looking at usage stats.
However, I see some attractive features in Ruby 3, do you think that's enough to get a comeback?
My main concern is jobs availability, as an employer I find it harder and harder to find good RoR developers and they become super expensive. As a startup you're start to think if you made a big mistake choosing Ruby , even if it's easier to build something, being so hard to find affordable developers offsets every advantage you had.
The ecosystem changed a lot, as it always did. Many youngsters learn that single language works everywhere, learn that server and frontend may share their code. If they end up using Rails they likely spend more time in their react files than anywhere else.
The reason why I don't find nice RoR jobs anymore is because most of them are looking for a react/Vue developer with rails skills and not the other way around.
Also I am not sure why you think there should be cheaper Devs. Cheap Devs means unskilled labor, which means a less optimal code base. The situations I built RoR apps for always had a high testing, optimization, quality standard and liquid development process, essentially using all the strengths rails has to offer. why they choose rails in the first place.