I think any cross-platform open standard is going to be at a serious disadvantage compared to a good native environment. There are just too many conflicting interests and cooks in the kitchen. This didn't matter much when the net consisted mostly of static content but as people come to expect richer and more immersive experiences the impedance mismatch is more evident.
I'm not so sure abut this, if you go back ten years most people had exposure to one platform and their web experience was limited to filling a few forms.
Now the experience is much broader, many users will have a smart phone, maybe a Mac at home and PC at work, then throw in the use of web applications like Google Docs and the whole interface landscape has become much more diverse.
Leaning towards the web as a user interface guide makes as much sense for most developers as anything else.
