> A few frameworks are strong contenders to be the successor to rails. Node.js is in the lead.

Node.js isn't a framework. What about comparing apples with apples?

Anyway, I think that the main change that's going on right now is that lots of web apps have a higher and higher percentage of the code written for the front end (web and mobile) rather than the back end.

Rails still has much higher productivity and tooling for back-end development than the Node.js frameworks I've seen for now, but that could become irrelevant for many startups in the medium term, just because a lot of the added value for them will come from the front end rather than the back end.