Often from developers who may, thanks to language Y, write more elegant code on the line / function level, but still create the same architectural mess as they did before in PHP. (Rails doesn't save you from creating a mess, neither does the broad separation of concerns of any MVC framework.).
There are thousands of ex-PHP developers out there that think they are now better programmers because they now use Ruby or Python, building thousands projects that proof otherwise.
Five to ten years from now, people will be bitching on HN about legacy RoR software like there's no tomorrow. And they'll probably be blaming the language and/or the framework.