Well, what you said would be true if management was sympathetic to the argument of "the language and framework we are using no longer serves the project well, so let's rewrite". Since they are not, projects are, 99% of the time, stuck with their first choice of language / framework for life.
What I meant was you can take a messy Rails monolith and do a million things to improve it (including breaking it into smaller independent services if that's your thing). Rewriting in another language is the last thing I would do if the project is big.
