Holdout client applications

If the web is so great, why are there still client application hold-outs?

Look at the popular PC applications of recent years: Skype, IM, Office 2007, iTunes, games. Why have they followed the client approach?

Application	Why client?	In two years
Skype, IM	Skype and IM require real-time communication between two parties. That's something that the HTTP request-response model of the web will never solve	Browser plug-ins are incorporating real-time technologies like XMPP - this will remove the need for separate client applications
Office 2007	Office 2007 has exploited its massive installed base, a far better user interface from the previous version, and certain browser weaknesses in page layout and editing.	Google Docs, Zoho and Wikis are already encroaching on Office's territory. These businesses will expand massively in the next couple of years, forcing less dominant Microsoft to lower prices.
iTunes	iTunes relies on an offline model, using downloads to iPods. It also relies on DRM, which browsers are not equipped to handle.	Both of these dependencies are crumbling (iPods are getting Wifi access, and DRM is fading) - I wouldn't be surprised if iTunes was replaced by iTunes.com soon.
Games	Most games rely on advanced graphics and animations, which browsers are not designed to support	I can't see browsers competing in the next few years, except perhaps for simple games like Tetris

Conclusion: except for games requiring powerful graphics engines, the web will continue to replace today's common client applications.