I am in technical diligence so I talk to companies going from start up to mid stage all the time (ie when they get bought or are getting a big investment). I've been doing it for six years now. My personal anecdotal observation is that companies now tell me it is much harder to hire for Ruby than for Python or Node back ends, for what that's worth.
I also, for whatever reason, seem to encounter more companies with "stuck on old version" tech debt on RoR more than on Python or Node. I'm not sure why this is.
I've found Rails over the last few versions to be very easy to upgrade.
Where I've had problems it's been 3rd party libraries that try to force alternatives to core behaviour like ActiveModel but then break their own API a year down the line.
cough Looking at you Dry::Validation.
You just do things like sticking to POROs for business logic it's pretty smooth.
I just follow the advice in the Sustainable Rails book.
Yeah, that's why I said I have no idea why that is. I'm sure it's not caused by Rails but rather some kind of secondary associative reason. (ie, rails devs leave and they have a hard time replacing with seniors or something). Coming from a Python background I find it weird. But it's definitely a thing.
It really depends on the project size and amount of dependencies. Ruby is very flexible, so dependencies can make a huge mess. Vanilla Rails doesn’t have those issues.
I also, for whatever reason, seem to encounter more companies with "stuck on old version" tech debt on RoR more than on Python or Node. I'm not sure why this is.