I've seen dozens of Rails projects going in production and many are still there. Same thing for any other programming language I guess. For normal sized companies Rails is OK.
What matters is: do you still find developers to work with your technology after 2, 5, 10, 20 years? If you don't, you have to move the project where the developers are. In the case of Rails they are still here for hire.
I want to like rails and to see it do well, but it's not keeping pace with the rest of its peers. As competitive as web dev is these days, it's not sufficient to just be rails, you need a ruby alternative to rails as well. Look at javascript. Nobody uses javascript straight up, there's a multitude of rails-like frameworks for javascript. A new one is made each day, and they have staying power.
Ruby has Rails, and some might argue that metaphorically speaking Rails has Ruby, by its polite little balls. Unfortunately Rails's star power is outliving Ruby's and given that new Ruby devs aren't being born every day, it's not hard to see that that's bad for Rails.
I'd love to see rails move to JS or Elixir or something that'll get people interested in it again, and KEEP them this time by being written in something fast.
In short, if you don't want to use Ruby, then don't use Rails.
Also, many large Rails services have some performance-critical parts written in $other_language such as Elixer, Go, Rust, etc. "Using Rails" doesn't mean you need to use it for every last bit.
I guess, if you choose Rails, there is more chance you will build something beyond MVP as you get to focus on what you build not how.