Yeah it could happen. Or maybe it can also be an android smartphone device.

You talk about being innovative yet catering to the old demographic.

ANyway, what about a tablet with removable buttons

Why the hell some people think NX will be a tablet? It does not make any sense and there's not a single sign pointing towards it.

Sorry OP, hardcore gamers are determined to kill off consoles and handhelds. These devices are supposed to have no added value beyond games, they are supposed play games better than any smartphone, and they have to be beyond cheap. Gamers are killing their own hobbie, and so far the big 3 are doing little more than ridding it out until their is nothing left to gain.

The future of games is going to be streaming services and touch controls, and highly overpriced, but thats the way the majority want it.

Hard to tell at this point. Nintendo did say that NX would "Surprise" gamers. So it could be a donut with a circular screen or a Nintendo tablet or even a Nintendo Phone. That would surprise me for sure. But I don't think they will go this route. I doubt if Sony will return so I think Nintendo has an open space to think about their decisions wisely.

Yeah there's no sign at all. None. Nope. I mean this:

Couldn't possibly ever, never, not in a billion years evolve into something like this:

It's unpossible. Clearly. 

Good to know that you also rule out this illogical possibility. It would be like saying an apple could evolve into a pear just because they look similar.

Clearly impossible. It would be like the ending of Interstellar. Just a radical leap. Impossible. I would fall out of my chair because Nintendo did nothing at all to prepare me for the possibility *goes back to playing on his Wii U tablet*. ;)

Tablets/mobiles suck donkey scrotum as gaming devices.

Isn't entering the mobile market with their own mobile focused android tablet (I highly doubt android will be on any nintendo console ever anyways....) completely averse to literally everything they've said about their mobile strategy so far, though?
They have stated that their approach to mobile (as well as qol) is done with the explicit goal of drawing people towards their dedicated handheld/homeconsole systems. They have partnered with DeNA to develop an overarching infrastruckture to interconnect their systems not split them further apart. If you ask me, it's likely DeNA will have some kind of input on whatever new OS they develop for their NX/Next handheld/next homeconsole too.
I also doubt they'd try to enter a market that by all accounts is fairly unstable to all but the biggest players, aka Apple and Samsung and possibly shrinking already.
They'll be doing better with the distinction of having something unique of their own.
That being said, do I think it's impossible for the NX/next Hamdheld to have a tablet inspired formfactor à la the gamepad? No not at all. But I don't think they'd ever limit themselves so much as to go with a touch-only interface. There will be physical Buttons, there will probably be a touchscreen too and it all might possibly be doughnut shaped.