It didn't take a mind reader to see that the ban on same-sex marriage would pass. The people who pandered the issue did it very well. What they either didn't realize or hid from the voters was that the issue wasn't the institution of marriage. The institution of marriage never has been in danger.
What is due to change is the civil status of marriage. Civil status is like being a juvenile or being mentally incompetent or being a resident of a state or county. Each of these statuses brings with it certain protections, certain benefits and also responsibilities. The biggest benefit that most people will recognize is the check box on tax forms to file as married. The ability to check that box is a result of the civil status of being married. The benefit of that status is now denied to an entire class of people and that bar is a part of the constitution. That bar is not subject to debate.