future life cycles
I wouldn't put it past MS to shorten future life cycles and support like Apple. Any previous OS life is "X" from date of new version release or becomes retired after two new versions whichever is shorter.
Quickly halt old OS sales (according to MS http://windows.microsoft.com/en-GB/windows/lifecycle WIN 7 Premium is still available pre-installed on machines at least for another year even though mainstream support has ended.) even though its replacement has been out for over 2 years.
Only corporate licencing Programs / Subscriptions would get downgrade rights and again restricted time (longer costs exponentially more model).
Biting the hand that feeds IT
