With the exception of the SNES, every Nintendo home console has gotten two original mainline Zelda games. I don't know if we'll see another HD remaster or not, but odds are we'll see another Zelda game. It's one of those franchises that will pretty much always sell 3-4 million copies no matter what hardware they end up on. They'll probably do what they did with Majora's Mask and reuse the engine for Legend of Zelda Wii U, which will cut the development time in half. I think Hyrule Warriors 2 is a safe bet, too. HW sold above expectations, and those games are cheap and quick to make since they rely heavily on recycling aspects from the previous game.
Why? They've yet to remaster any Wii games, and Skyward Sword is one of the later Wii releases.
Well, to be fair, you're using your own internal logic as well. The two Wii games that we've seem ported/downported to the 3DS are Donkey Kong Country Returns and Xenoblade Chronices. Outside you simply wanting it, I don't really see any kind of pattern to suggest that TP is a next logical step. It's more logical to expect more N64 remasters since the 3DS has had three and that is better suited for the 3DS/New 3DS to handle. If anything, it makes much more logical sense to expect Twilight Princess to get a HD remaster on the Wii U, since we got Wind Waker already, and the hardware is more suited for it.