(And ENDA would have been passed in the last attempt, if not for trans inclusions, so...?) The current administration refused to support DOMA because it believes it's unconstitutional, so while we had no national budget in place, Republicans were scrambling to find money to defend it. You can see things crumbling, little bit by little bit.
Note that in the poll (as the article said), the people most likely to vote for permitting same-sex marriages are young women, the most likely to vote against are older men. Which one of those groups comprises a large majority of our current legislative bodies? It doesn't really matter what the votes want; such legislation for or against is driven in our political system on the sponsorship and committee levels, which can get even supported bills dumped out in the cold by manipulating the process. It's just how the game is played.