So basically Rails is not as popular as it was before, but it seems to have influenced other successful frameworks.
I'd think that part of the reason is people realised that Ruby is slow, and sometimes it matters.
From time to time I get seduced by the romantic idea of building a simple JSON-spitting Go/C#/Java backend for an app, but then I realize that I would have to hand-code an enormous amount of functionality that I would get for free with Rails.