I don't really understand this criticism. If your web app is simple/static enough, then by all means use Rails. Everything will be simpler. But there are an entire class of applications that can't be built with that stack.
That's a very bold statement: "can't be built with that stack".
A large portion of apps aren't built with Node or React, they're built with, say, Rails, Java/Spring or .NET backends and a front end framework like Angular.
I get the theory behind React, the reality is that it is often a complete mess.
Since when was Rails limited to "simple/static" sites? I see the opposite all over the place these days - React + entourage for the most basic dynamic sites.
