Petz, that was a creative conspiracy theory, not very likely though. I can not remember a single major Microsoft release that wasn't delayed by at least six months commencing in the year of its scheduled release. A far more likely cause is good, old fashioned testing and verification of 3rd party drivers and boundry cases in Microsoft's horde of APIs.
Believe me, if Microsoft could have been on stage last April along with Linux for the launch, they would have. However, Linux has a simpler release model, they can release once the kernel and a minimal set of drivers is complete. Microsoft has to support all sorts of desktop configurations and coordinate a much, much larger set of OEMs.