Despite common belief, MS actually wants the best browser in the world. But they want it to be noticeably the best.

The fear MS would have if FF did their browser is that the FF browser for Windows offered no advantage over the one for Linux or the Mac. Or even worse, the Linux version of FF was substantially better than the Windows version.

Now you can argue that IE isn't as good as Chrome or FF, but at least MS knows that's their decision. They've allocated their resources and made their business case. If FF is providing the browser then MS could end up in a situation where the most visible end user feature is out of their control.

Let me flip the question on you. Do you think Apple ever would/should simply let FF or Chrome be their iOS web browser and stop doing Safari mobile?

Since Microsoft controls the OS, they can ship a browser with defaults set to sites under their control, like msn.com and bing.

My assumption is that they consider those properties as revenue (or potential revenue) sources.

I'd guess it would be kind of a PR nightmare for them though. Nobody questions those defaults when the browser is owned by Microsoft.

Microsoft provides a range of different development tools and programming languages for web development. There is the modern stuff such as ASP.NET, Silverlight, etc, but lets not forget VBScript, ActiveX, etc, the latter not widely supported by other browsers.

Microsoft has more to lose technology wise by dumping its browser than the other companies do.

By having a browser on one platform they can use hardware acceleration on the browser making a win for both and keeping their hold on both.

That's the theory anyway. They'll probably screw it up bit that's the theory.

It's already beginning to happen. For example: http://www.winrumors.com/bing-powered-u-s-searches-rise-to-o...