This assumes that enterprises can use Win 8 in a productive manner at all
At this point in time I find that Win 8 is counter productive when compared to earlier versions of Windows. This is due to the way the MS designers have concentrated on making Win 8 a consumer OS and not a productivity OS. I'm sure the usual MS pressure to close down the earlier OSs will eventually force some enterprises over to Win 8, but I don't see it happening very soon.