An intruiging, some would say wonderful, thought.
What if Microsoft were to suddenly stop developing Windows?
Firstly, in the short-term, very little would change. So many businesses are still running versions of Windows on the desktop that are over fours years old, because there have been very few real advances recently in Windows' development that have actually added any real functionality that most businesses require. This gives plently of time for businesses to evaluate alternative solutions.
On the server-side, anything provided by MS servers can already be provided at least as well by a multitude of other platforms - most of them free. The only point where this may be of slight trouble is with Exchange server (for those unfortunate businesses that rely upon it) since it uses proprietary Microsoft protocols to communicate. However with a little work any administrator would be able to move a 100-1000 user-base network over to open standards in a matter of 8-12 weeks with good planning.
If this scenario were to arise, the home-user market would likely move in a different direction. Of course, everyone that already has a Windows PC would be more-or-less unaffected to start with, their OS will continue to 'work' as well as it did before. However, Mac OS/X would more than likely start to gain an awful lot more ground in the first year or two. It is a well-known, user-friendly platform that already has a good developer and user base and proven stability.
In the meantime, Linux development groups, commercial or otherwise such as Mandrake, Red Hat and KDE will begin to receive sponsorship from OEM's who wish to remain in the i386 market. The products will benefit from vastly accelerated development in response to increased commercial demand.
Since demand for open source OS's increases dramatically, support for these amongst hardware and software producers will increase.
Linux and OS/X will replace Windows as operating systems for which it can be safely assumed that any new purchase of hardware or software will be properly supported. Other OS's such as xBSD will enjoy a more limited, but certainly increased support from hardware vendors.
Within two years, what we know today as 'alternative operating systems' will have surpassed Windows' user-friendliness (having long ago already surpassed its stability, functionality, security and intercompatibility) and become the norm in everyday computing. Windows will be vaguely remembered as that thing we were forced to use and crashed all the time.
