ya if PS4K is real & NX is just slightly more powerful than PS4 with an upgraded Gamepad than that sounds alot like their current situation with Wii U.
It would be a very similar situation.
In all honesty, I don't know if there is a silver bullet approach any which way for Nintendo. This is going to be tough for them on the console side, they have given up too much of the market and need something incredibly impressive just to get on people's radar.
They won't get any developer support without a powerful machine though, and I think we forget the whole crux of the hardware model is that the hardware maker gets licensing fees for doing all the difficult of marketing/R&D/hardware design. That's why 3rd parties pay $5-$10 every copy of every game, because they don't want to be bothered with that.