I get the impression that Dahl knew ahead of time that he was working with some serious limitations with event-driven programming such as it is on V8. He's a smart guy, he had to have known how much cleaner things like Erlang are.
At the same time, we have a bunch of zealots who've never done any event-driven programming on C, Lisp/Scheme (CPS), or on Erlang who think it's the best thing since sliced bread because it's FAST.
I'd argue that the main advantage of Rails wasn't "speed" and I don't think it ever was.
Rails' main advantage was making the human fast. Node.js reeks of misguided pre-optimization to me. It doesn't make building a product any faster.
Could just as easily build a web app with CoffeeScript + BackBone + Flask (python), or Clojure, or Ruby, or whatever.
The single-page app paradigm needs to be pushed in terms of integration and productivty in order to get adopted. The backend involved is almost immaterial, it's just a JSON API conceptually.
So why are we pretending Node.js is somehow a successor to Rails when it doesn't actually improve on anything in terms of product or performance?