> Here are Ruby and Rails measured against Node.js, the popular JavaScript framework.

> Finding the next Rails or Node.js

This is nitpicking, and it looks like you understand the difference. But in these sentences you are comparing a vm+framework(ruby rails) against another vm(node.js).

The thing is there is no rails for node only a bunch of contenders[0].

js gained its traction with humankind putting a vm in your webbrowser on every machine.

[0]: http://nodeframework.com/

It was the new hipster language and slowly is losing this image. There are new hipster languages now. Most people who learn Ruby/Rails already know it well enough at this point that random google queries and stack overflow questions would be out of place and less new developers are coming to the language.

IMO this is all just a natural process of maturing