Don't think it ever has although Xbox (and PS4) are close enough to PC architecture it should be doable (and lets face it, its actually seen as a strength for PC gaming). As long as they maintain backwards compatibility it shouldn't be a deal breaker.When has a console been superceded by a more powerful one in the same generation by a manufacturer, especially within a year, I'm curious?
Probably wishful thinking though, I doubt the effort and cost involved could be justified by revenues.