Well, the quality of those endings, or the level of satisfaction one gets from those endings, matters a lot. If some endings are way more satisfying, gameplay-wise, than others, why would anyone pursue those other lesser endings?
You have to remember here that a lot of this stuff is also subjective. What you may enjoy may be different from the next person. And there is also the matter that Larian tried to put in something for everyone but not everything is for everyone. Nobody is likely to see everything and not every bit that was put it was merely put in based on expected popularity either. There is a lot of depth to the game. I think a lot of the beauty in this game will be about all sorts of players finding paths and outcomes they really enjoy even though on the popularity poll those might not be near the top.
