If you've ever wondered why it's so long between updates for Windows, a post on the Engineering Windows 7 blog about Microsoft's development process will give you an inkling. While engineer Larry Osterman describes the approach to Windows 7 as "dramatically different", it's still amazingly procedural:
Instead of being fairly hierarchical, [Windows 7 lead]Steven Sinofsky has 3 direct reports, each representing a particular discipline: Development, Test and Program Management. Under each of the discipline leads, there are 6 development/test/program management managers, one for each of the major groups in WEX. Those 2nd level managers in turn have a half a dozen or so leads, each one with between 5 and 15 direct reports.
With that kind of approach, even an apparent no-brainer decision like having a shutdown button you can easily find can take a while. It also explains why stripping out so many default apps makes sense -- less hanging around means a smaller code tree to support -- and why Vista SP2 will be out first.