Both games are on multiple platforms. Whether you measure their total, or on a single platform (TP Wii vs Ocarina 64) the game with the most copies in players hands in Ocarina.  But we are going off track; the point is, no, you do not have to compare to Twilight Princess for recent Zelda sales to look small; compared to Ocarina or the NES original, they're comparatively small also.

As I've said, things like cultural impact do play a part, as with TLOU, so putting a number like "3-4 times" to it serves little purpose, but sales are the final decider, as a game cannot be among the biggest of the generation if not many people even played it.

I get what you are saying, that to you Zelda will be one of the best/biggest games of this gen, and thats fine, but you need to realize that to the market at large, it will not be. It will be highly rated by critics and well liked by the small and shrinking band of Nintendo diehards, but most gamers will not even care about it.

But my point is that Zelda U will not have small sales compared to best selling Zelda's (NES Zelda, OoT, TP), it will sold more than previous Zelda SS and handheld Zelda will also outsell previous Zelda.

Again, "biggest"/best game doesn't equals best sales, thats is a fact. Wii Play is one of the biggest seller of previous gen, do you consider Wii Play for biggest/best of generation!? So you basically saying that TLOU isn't one of the"biggest"/best game of previous gen!?

It not just for me, Zelda U will be one of the "biggest"/best games of generation, same like probably The Last Guardian or Uncharted 4..or TLOU last gen, all those games will (or were) attract great attention of whole gaming community and gamers not just people who having PS4, PS3 or in case of Zelda U Wii U. Do you realise that Zelda U have great chance to be GOTY or even GOTG, only that make it one of the "biggest"/best games of generation. Again, one of the "biggest" game does not equal one of the best selling game.

So our disagreement seems to break down to 3 points:

(1) I think sales are a primary factor in what the "biggest" games of a generation are, you don't.

(2) You think Zelda U will come close to Ocarina/TP level sales, I don't.

(3) You think Zelda still has strong appeal to the gaming mainstream, I don't.

Actually everything Aonuma said about Zelda U is proof that they listening what Zelda fans wants. It also fact that majority of Zelda fans dont want realistic Zelda.

Actually if Zelda U is again cross release like TP was, definitely can get similar TP numbers. Everything we see or hear about Zelda U is great, so I really don't see any problem.

Nintendo doesnt care what PS/Xbox owners wants because they don't release games on those platforms, they care what Zelda and Nintendo fans wants and in same time making game that again will be very unique and different than anything else on market (thats one main of reasons why Zelda series is so great). 

Its obvious that you will listen those who love your product and actually buy it, not those that don't like Zelda series at all and want something different.

They slatured because huge mistakes they made with consoles, not with games. Games are great and they are selling phenomenal regardless instal base.

Software sells hardware. Wii U's failure is what happens when you ignore the gaming mainstream, which is now on PS4/Xbox One.