Blame the language and not the platform is what you're essentially saying. Ok so initial payload can be what 600kb per your argument. But at least once I have delivered that my actual interactions on the server side can be somewhat a minimum instead of re-rendering more HTML and sending across the wire to the handset.

That being said yes you must develop on a crappy computer if you want to be known as dev that's known for making apps snappy. Is there a lot of fat one can cut from these frameworks yes... but I think Atwood's initial argument is that android just sucks with Javascript. The many cores, single thread per tab just makes the experience anemic with rich web applications.