I think, that Nintendo's Wii U console is now powerful enough to run serious games, even as 8th gen console. So, why Bethesda do not make games on it? Seems like game bryo was ported, and rumors says that idTech5 works on it.

The Wii U is notoriously difficult for 3rd parties to work with. It is somewhat less powerful than an Xbox 360, and Nintendo has some of the strongest first party stuff--most owners buy it for Mario or Zelda, so it is less appealing for 3rd party developers.

Because it svcks.

Let's not try and sugarcoat it, just face the brutal reality which is indeed that the Wii U svcks.