Well I know the creators would make more money by
1. Reusing Twilight Princess graphics like they said they could have done, making less cost on production because it would take less time, and all the other factors that changing graphics cost.
2. The game would already be out and they'd already be making profits on it. (They even said the game would already be out if they didn't change graphical styles)
3. Realistic graphics garentees great sales, because they already know realistic graphics sell better comparing wind wakers sales to twilight princess sales.
So, ya i think they changed it because they felt thats what zelda was. If they wanted to make money, they'd have used TP's graphics.
So to answer, Skyward Sword IS a marketing strategy because it's a zelda game and zelda games make a crap tons of money, but it ISN'T if you think they made it solely to make the most amount of cash a zelda game can make. But ya, what ChargewithSword said, Twilight Princess was a gaurentee money making game, they took no chances. They made the game everyone wanted. Realistic and like Ocarina of Time. Oh, Skyward Sword isn't a marketing stratgey, but Ocarina of Time remake definately is.