Wouldn't this mean that Zelda U will sell less than the WW remake? ^^ But yeah, I've heard (and seen) that the second games on any console sell less for the Zelda series...
Indeed we haven't had the situation where the first game was a remake yet, that'll be interesting to see .
EDIT: And this also affects the 3DS, where it's first game was the OoT remake. I hope they don't mess with the other's sales then!
Yeah, it'll be very interesting to see how this will effect Zelda (both on3DS and Wii U)!
AlphaCielago also brought up an interesting question; when, if ever, will we see 3 Zelda games on the same console?!
I just realized that we do have somewhat of a precedent here.
On GameBoy Advance, the first Zelda was the remake of A Link to the Past along with Four Swords, and the second the original game Minish Cap. Minish Cap sold way worse than the ALttP remake. I hope that this instance doesn't set the example, but I think (pray) that in that particular case, it's the exception as ALttP is legendary while MC is of relatively low quality.
And saleswise, having a third would indeed be interesting to see just what would happen. Would sales fall further or bounce back up again? We don't know, this hasn't been done yet. Development times are too long though for it to happen I think, unless they go ballistic on remakes which they shouldn't. If timing is correct they can only have up to two original games on each console considering the 'tradional' console life-cycle.
The GameBoy is the only console which could be considered for this comparison, but it's tricky. Putting both GB and GBC together as one, it has four Zelda games, but actually just two. Link's Awakening has a coloured remaster and the Oracle games are similar to Pokémon's concept. Still, in sales they would translate to LA > LADX > OoA > OoS, or combining them to LA > OoX. But like I said, there's no fair comparison in it.