Yep ultimately public decides, and they are deciding. the fact that 3D seats are selling and not empty shows that audience wanna watch this in 3D, otherwise there are ton of 2D shows to go to, if audience just wanted to watch in 2D, they would be selling much better.
That said, I am a bit disappointed by 3D share in US as compared to rest of world, but I guess that's bad rep for 3D over the years in play. With WOM post release, US can improve as well.