Ruby on Rails is pretty cool and nice to work with, but in my comparison it'd probably be somewhere next to Python as far as performance is concerned.

Oh, also, for a while I ran GitLab which is written in Ruby and still run OpenProject, which also is. Both of those underperformed and wanted both unreasonable amounts of memory whilst also running slowly when under load.

I'm yet to see a Rails codebase that can actually compete with the likes of Java/.NET/Go, since projects like Gitea are snappy and use about 1/10th of the RAM. Then again, nobody really picks languages/tech stacks for their performance outside of a few industries/domains where that is indeed necessary (HFT?).

Most of the time people just choose whatever is the easiest to work with, has the best integrations/frameworks/libraries and will let them ship features in a timely manner. Now, upgrading old Rails projects, though, is something that I cannot recommend doing. Very much not a fun experience.