Yes, it will happen. My state was the first in the union, and already, it’s no big deal here. When it happened here in Massachusetts, it was through the decision here came from the State Supreme Judicial Court finding that discrimination against homosexuals in marriage rights is unconstitutional per our state’s constitution. At the time, the public was fairly divided. But it took Republicans several years to mount a legislative attempt at a constitutional amendment, and that failed. They then took several more years to gather signatures, get them certified, and get the legislature to act on the possibility of constitutional amendment by ballot initiative. That also failed. In that time, public opinion had massively shifted. All the lies the Christian Right had spread about gay Scout leaders and gay teachers teaching kids to be gay, and wholesale marriage break-ups with everyone suddenly marrying a same-sex partner turned out to be pure hogwash. Currently, I think the polling shows that 66% of straights here favor marriage equality, and that number keeps growing.
Nationally, it’s more like 53% support marriage equality while 45% oppose it. And that has changed drastically over the last two decades. Just 15 years ago, only 27% supported it while 68% opposed.
But hate and bigotry die a slow death. 150 years after the end of slavery and 50 years after the civil rights act, we still have the KKK and skinheads with us, and racist dog whistle politics still works well enough one of the tow parties resorts to it on a regular basis. Racial Prejudice isn’t dead, it’s just mostly in the closet. It’s dying, but it’s a slow, agonizing death.