You think if the Wii U was cheaper it would have sold significantly better? I'm highly skeptical of that. The thing is just incredibly unappealing.
No, the Wii U's problems go beyond price. But if the NX is cheaper, has twice as many 1st party games, at least some 3rd party support, better account infrastructure, the games are cross-compatible with the handheld, and it has better marketing... then yes, it could be successful.