I always thought Windows 2000 was the point of over-service for Microsoft. The book linked below puts a date on the point when Microsoft could and should have created an autonomous division whose task would be to create the platform that would eventually disrupt its core business.
Clearly Microsoft did not do this but Apple, with iPad, did.
In September 1999, Kodesh wrote a memo to Gates and Ballmer under the heading “Starting from Scratch.” We need to kill Windows CE for those categories, he argued. Win32 is not an advantage; it’s a tax on device design. It served to further Microsoft’s strategy but not to help consumers. Given all their other alternatives, electronics manufacturers wouldn’t pay the tax. Kodesh wanted to take a small group of developers and work solely on developing the best software for information appliances, unconstrained by the needs of the rest of the company. Gates rejected the suggestions. “It’s very disappointing you feel that way,” he told Kodesh. “We don’t have time to start from scratch.”
link: Who Fatally Wounded Microsoft? It Was Bill Gates. « Mike Cane’s iPad Test