And he has come to the conclusion that he is making an optimizing compiler.
Perhaps the reason he thinks web frameworks will help us 'approach native performance' is because he doesn't know what native performance is? Could you really understand web performance if you don't understand native performance?
There are a lot of people who create things and learn the hard way what they didn't know at the beginning. Creating Ember and then talking about going back to Flash, says all that needs to be said about his credibility.
Haha, he is the creator of Ember.js. I think he knows a thing or two about web frameworks ;)