I have to disagree here. It's probably true that 2009 is not the year of the GNU/Linux desktop, nor will 2010 be. If it does happen it will certainly take a long time, and maybe it will never come.
So what OS would we be running in the cloud? There are already
a few such services. But I doubt that many of today's GNU/Linux users will switch to a web-based OS any time soon. I like to tweak my software, and while there is certainly room for web-based computing, I would be concerned about not being able to tweak and have complete control.
Stopping the OS wars with a universal web-based version would eliminate competition, and hence slow innovation. No browser wars? As a web developer, the browser wars annoy me as much as anyone. But even I would not want to have everyone confined to one browser, simply because none of them are perfect, none ever will be perfect, and competition between them makes them all get better. If the change you're describing took place a few years ago, we would all be using Windows and Internet Explorer because those were mainstream. The decision would have been made for us by the service providers, and I wouldn't be using GNU/Linux right now.
I think the biggest concern should not be switching to one system or another, going cloud-based or desktop-based, as there is merit to all different types of solutions. What I want to see is interoperability, so that whatever machine or virtual machine I want to use, whatever desktop OS or web-based managed system I choose, I should still be able to create and view content, run all programs, etc. What happens if I want to switch web-based providers and move my data over? Because the one thing that will never (or should never) happen is everyone agreeing on one solution.
As for netbooks being the desktop of tomorrow, that just can't happen for physical reasons. They work fine for websurfing, but the screen is simply too small for anything else. It has 1/4 the area of my desktop monitor, and I only have 1 -- lots of people have 2 or more monitors, and a netbook would be a major downgrade.