I think the next console will break the cycle. I think we'll see a rise in sales from Wii U to next console and it will start trending the other way. NX (or whatever) will be more like GC sales (20+ million).
I'm basing this off nothing substantial or concrete, just a hunch. A hunch that Nintendo will look at why Wii U failed, correct the errors, shed this identity crisis they've had of catering to casuals and go back to just making good games on hardware that everyone can understand and get on board with. It's a big hunch, but I think it would automatically earn them 10+ million more hardware sales.
Like I said, purely speculation and not based off anything. I just think they'll take a long hard look at who they are and where they want to go and figure out how to win the general public back next generation. Their games always sell well - it's the hardware that's confusing.
It'll be awhile before I figure out how to do one of these. :P
