What's the point of no return for WiiU?

[Seece]

So we've seen a few of Nintendo's attempts to reignite WiiU fail now, the bundles, the 'price cut', Super Mario 3D World, Zelda remake.

At what point do we say, this thing isn't going to take off or even sustain 5m a year??

When/if Mario kart doesn't do anything?

Smash?

Price cut to $199?

Something else??