> What matters is not when Windows XP was originally released, but when its official support ended
Well, or when a serious replacement arose (because XP was aging at that point). Vista was quite alright if you had a beefy computer, but for the majority I guess it took until 7, which would be July 2009.
Not saying you're wrong or that support should be dropped, I'm just not sure end of support is the best date to use.