The iphone might yet change this.
It strikes me as a colossal ''duh''. Would any of us be here reading this site if Paul Graham hadn't had a similar insight with regards to selling shit (via the Web) in 1995-96?
What can you do in a native app that you can't do with some javascript and a pretty webapp these days :/
The days of native apps is ending. On the desktop, on mobile phones, everywhere.
Javascript-based apps are bad enough on desktop, I don't want to have them in my mobile device.
Webapps are the true "Write once run anywhere".