There is none. I'd consider Ruby on Rails not relevant nowadays for anything but small shops. You can find exceptions, and for example the whole Gitlab is written in Ruby on Rails, but you can find exceptions for Cobol too.

Personal biases are involved I'm sure. Ruby is fine, Rails is great, I just don't see it used very often.

On the other hand, I still see a ton of JEE being heavily utilized in a number of sectors. Ruby might have in the past taken over Java for small shops that basically create a frontend to a database, but I'd argue that was never true for the enterprise sector.