Xbox One has almost outsold the wii u

The wii u is struggling to stay relevant. Is it just me or does every article that talks about next gen seem to focus entirely on the ps4 and xbox one? Both consoles are selling way beyond what the companies estimated they would. And both are selling this well with no games. (Ok, maybe a few games.) The wii u on the other hand, has more games than the xbox one, has been out longer, and is cheaper and yet will be left in the dust this year, probably even with the release of smash bros. With the sales as they are, should Nintendo double down on the wii u or let up?