osed125 on 03 December 2012
If both companies intend to launch their system by the end of 2013 there is no turning back without loosing money. Games are already being made and both companies have spend too much money to just "delay" the new consoles. So imo it doesn't matter if the Wii U sales are good or not, Sony and MS won't push there consoles launch (unless something major happens).
But to answer your question I believe the lowest the Wii U will do is 4m. Nintendo forecast 5.5m units by March and I believe they can achieve that goal. After that is pretty hard to say without knowing which games will be release.
Nintendo and PC gamer
