This article is absolutely ridicolous. First of all, "Web 2.0" and "AJAX" software won't ever replace Desktop Software, period. The first issue is Performance. JavaScript is awfully slow compared to real programming languages, and this won't change because of some language-specific features. An eMail or calendar application is certainly doable with JavaScript (even though they still aren't as good as desktop software because of the latency). Perhaps even word processing and spreadsheets will be possible with an AJAX app, even though the current AJAX "word processing" and "spreadsheet" apps are ridiculous compared to MS or OpenOffice. But other things, like image editing, video editing, rendering and 3D games just aren't feasible with AJAX. JavaScript is too slow to compute stuff on the client and the latency is too high to do everything on the server, and also someone would have to pay for the server the work is being done on. It won't happen.
But even if it were technically feasible it wouldn't happen. That's because it doesn't offer many advantages over traditional apps. Sure, you can access your data from everywhere, but for everything that matters, that is already the case. For example, IMAP is spreading more and more - why on earth would i use some crappy AJAX eMail client?
And there's another very important reason why AJAX won't take over the World: privacy. There are a lot of things that i just don't want to lie around on someone elses server.
Secondly, high-bandwith connections aren't available for everyone. Think of people living in rural areas, and of people who just don't need it. Yes, those people do exist, and they won't spend 20Â/Month just to do what they already do with conventional software.
Thirdly, it's just not true that "All the computer people use Macs or Linux now". I study CS, and while most of my fellow students have tried Linux, nearly everyone returned back to Windows. That's because nearly every interesting piece of open source software is available for Windows too, while there is a lot of software that is Windows-only. An OS is just a platform for running software, and the software is what matters.
In the end, you even claim that Microsoft sucks. Well, the truth is, they don't really suck very hard anymore. Yes, Windows 1.0-ME were crap, but the Windows NT/2000/XP series is good enough for most people (I haven't tried Vista yet). I've never worked with Visual Studio, but a lot of people claim it's a superb IDE for C/C++. Then you have MS Office. It's not perfect, but it's good enough for almost everyone, and it doesn't suck any harder than it's primary competition, OpenOffice.org (In fact, OpenOffice.org's Base doesn't even come close to the functionality of Access and there is also no good replacement for Visio - no, Dia and Kivio aren't, and then there is Sharepoint and Exchange and a lot more). Claiming that Microsoft Software generally sucks doesn't help, because it's simply not true, and by expressing stuff like that you only make a fool of yourself.