Simple:  it's not a "technical" problem it's a management and policy thing.

VS / VC is targeting the "Platform" that Microsoft sells.  Microsoft is not selling XP any longer and is asking folks to follow the guidelines and policy that they have published.

with the release of windows 8  xp will be 4 versions back. it has reached the end of support and sales.  and for the small number of developers who still must support XP they can use VS 2010 or VS 2008 to do that.

that aside I personally would say that it's time to get the apps to WIndows 7 at least and stop using the XP OS for many many reasons.

a company that is using multiple vendors to make a system or device should make sure they are not shooting thier own foot.  they should have known that xp is end of life  and started the update / migration long before this happened. if they failed to read the published notices and makie the right plans that is not Microsofts fault.