Well, we're well on our way into unknown waters now. If mere shreds of legislation and judicial hair-splitting are all that's keeping legal same-sex marriage from becoming a reality, then society is surely ready for it.
But as I said, the waters are unknown. As the writer Donald Kingsbury said, Tradition is a set of solutions for which we have forgotten the problems. Throw away the solution and you get the problem back. Sometimes the problem has mutated or disappeared. Often it is still there as strong as it ever was. Society's insistence on monogamous, lifelong, opposite sex marriage was a solution to a problem which apparently we no longer remember. Will it now come back, in some guise or other?
We'll see. We've heard the wheels of history creak today, no doubt. Now we'll await the ramifications, which will probably play out long after we're gone.