@grigs has some really good analysis on this question. Device sensor capabilities (GPS, accelerometer, camera and so on) are the big tech piece missing from standardized HTML access. But as one of his five dimensions he also identifies the AppStore: monetization.

http://www.cloudfour.com/459/the-five-most-common-arguments-for-native-iphone-development/

I’m not convinced riding the AppStore is a way to build a sustainable business. But that’s a discussion for another day… :-)