DirectX 11 might be here sooner than expected, with speculation putting the launch of the platform within a year or so. Most interestingly, it is suggested that the launch of DirectX 11 will come standalone from the upcoming release of Windows 7, which may be a bit of a bone thrown to developers who got a bad taste in their mouth with DirectX 10.
Microsoft's choice to not port DirectX 10 to XP was purely a marketing choice, as it was demonstrated more than once that it could function normally under XP. As a result, many developers felt abandoned, particularly those who were and still are leery of Windows Vista. While at this point it's almost unheard of to imagine that DirectX 11 will make it to XP, at the very least having supporting for multiple platforms (Windows Vista and 7) will broaden some development horizons.