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.