While I realize the OP absolutely HATES Wikipedia, this is what they have on Windows XP and ongoing Microsoft support:
The original Wikipedia article does quote actual Microsoft sources for this information.
It makes sense to continue offering support for XP for some time to come, considering Dell and other computer manufacturers are still offering XP on brand new machines.
Even when support ends, it doesn't mean the software will automatically stop working, it just means Microsoft will no longer issue software updates for it. I know of a major metropolitan police agency on the west coast that is still using Windows 95 :11: