I think even Apple learned the hard way that people don't want just HTML (even full HTML5, AJAX, whatever) apps, and that connectivity is not so reliable that everything can live online in some cloud forevermore. There will always be a need for locally running applications, and I will always want to have things like a local mail client from which I can read email without an internet connection. Yes, web apps are great, but they are never going to fully replace running real applications on the local system.
As to fluffy. Yea. I just bought a new netbook and I'm seriously considering finally ditching GNOME while I'm at it. It's not just web stuff that I think of as "fluffy". I probably won't ditch GNOME as it's so ingrained in Fedora and I want to keep up with what's going on, but there's a strong part of me that wants to go back to the days of enlightenment 0.17, complete with esd. All of this talk of being a window onto the web is something I generally look on as fantastic BS that won't ever really work until we have internet links that don't rely on physical cables, wireless networks, or other real world non-cloudy buzzwords to actually make them work and remain reliable.