But will not reach PS4 level sales.  Overall I think that with Zelda as a launch title, proper releases of classic games like a new 3D Mario, Metroid, NEW Star Fox (not a cheap N64 remake), 3D Donkey Kong, Pokemon, Fire Emblem etc we could see a very STRONG start.

Follow that up with newer franchises like Xenoblade and Splatoon with a few third party contracts for other exclusice titles, and the NX will be a success for Nintendo and in the end profitable.  The reason it will not reach PS4 sales is because the PS4 has become the home for 3rd party multiplats.  Just having those games on NX will not be enough to beat Playstation at this time, but Nintendo has more than enough IP (more than any other console maker) that with proper 3rd party support (NX exclusive titles) it will have a powerful identity as the console everyone will want ALONGSIDE their PS4 or X1.

I also feel that while the NX will not reach PS4 level sales, it could still outsell the NEO version as NEO will offer nothing new to the table, while the NX will be a whole new experience.

EDIT:  To put a number on it, 60 mil.  It will not sell as much as PS360, but will outsell the X1 and N64.  It will also be profitable for Nintendo.

I'd love to know how Nintendo is going to handle the home console and handheld parts before making any predictions. But yeah, beating the N64 is still an achievable goal, specially if we count handheld.

a bit too early to make such predictions no? no info on price, hardware, software, gimmicks, what the competition will be...

let's check in a few months :)

It will not reach 20mil lifetime

It still depends on too many variables that we dont know of, to make a reasonable prediction, even a bold one I might say.With that being said, it will obviously pass Neo sales, just because Neo will only cater to the diehard PS fans, since casuals will buy the regular one since it will be the cheapest.

Well this also includes a bit of a prediction on how they will be handling their software releases.  There is a bit more to my logic, and I touched up on it in my OP, than just saying "Nintendo will do this much because I say it will".

Zelda won't do nothing. For a console to succeed they need multiple games like Zelda and third party games. As for my estimation it will do Wii U numbers if PS4 Neo takes off smoothly.

I would be willing to bet against that!  ;)

Zelda alone will ensure a smooth launch.  E3 will shed a bit more light on this, but I have a feeling it will be comparable to Witcher 3 in scope.  Some people, like myself, will upgrade from WiiU to NX for this game.  Most people who do not have a WiiU yet but want this game will go for NX just for the superior version (if my prediction on power holds up).  See Twilight Princess sales for reference to this fact.

And of course there will be other games.  Part of their strategy is to have a steady stream of games exclusive to the NX right out of the gate (why the WiiU is dead this year).  It does not take a rocket scientist to see that.

The Neo is a PS4, it will have all the PS4 games and won't have any game that's not on the PS4, so why separate the 2 skus when Sony itself doesn't?

The PS4 is starting with 40M as of now, probably over 50M by the end of the year, so there's 0 chance it will outsell it by definition :)