Not a chance, XP Pro support has a greater support life than the Home version. I don't know how they would go about determining who has home and who has pro versions as there is no distinction in the current security updates doesn't differentiate between home and pro, just XP SP1, SP2, etc.
As for "then what," by the time it happens windows 7 will probably be on SP1 or SP2 by then (who knows even windows

and Vista will be the winME of the 21st century
