It's all in the numbers at the end of the day.
Indeed. And the numbers show that you lose money if you make decent Wii U games, and you can relatively easily turn a profit if you make shovelware.
Most Microsoft and Sony customers know what games they want, and can tell the good from the crap when they're buying games - so good games sell well and make decent amounts of money, and crap games suffer. Even those who don't know much about gaming can usually pick up on what's good and what's not just by seeing the tv adverts, the game charts, and hearing general buzz.
By opening themselves up to as wide an audience as possible of non-gamers and casual gamers, Nintendo have a lot of customers who don't know much/anything about gaming, and when they do buy a game they'll buy any old shite. With no advertising of premium games, and the charts full of absolute drivel the problem is exacerbated - as more non-gamers buy crap games and eschew the half decent titles.
"I don't really know which of those games is good, but that £20 one with twelve different sports games included in it looks fun and there's bound to be some in there we like, Mabel. Look - it's got darts. Bert will enjoy that. And it's got quoits. Agatha loves a bit of quoits. That £35 one doesn't look like our cup of tea at all..." said the average Nintendo customer, yesterday.
Nintendo's first party titles will do okay. Everyone knows where they stand with Mario games, and know they'll get a polished and family-oriented game. But when it comes to third party titles, you're better off spending £10'000 making a shite party game than spending £1'000'000 on porting a good title.
As for making premium exclusive titles for the console? No chance. You can't sell enough to break even, even if you include the game in one of your main console bundles.
If Ubisoft make a second Zombiu game it'll be for the xb1 and ps4. The U might get a port. Makes more sense to just cut their losses and walk away from the title and the platform, though...