You're assuming the "next-gen" NX will be a PS4-level tech.
It probably will not be.
I'm guessing a unified platform, with the handheld being far and away the main platform, and that will be about Wii U level in power.
The home variant (or home dock) maybe will bump that up so that the same games can run on TV at 1080P resolution with maybe a few extra effects.
So from that POV, I don't see it being much of an adjustment for Nintendo, much like going from GameCube to Wii was not exactly a technical jump for Nintendo.







