I don't think either of them are even close to doomed. The Wii U will build a library of major Nintendo first-party games and still do well over the holidays, while the Vita continues to rack up games of all types (I want Terraria)--all the Vita really needs, in my opinion, is for developers to switch over from PSP support, which is slowly happening.
I think they will both end up in the 40-45M range. The Vita, especially, will be around for a long time.