We want a minimalist libertarian state that hands out contracts to consenting adults. We don't want a Big Moral Government who takes the place of churches by stipulating the kinds of acceptable marriage.
Okay. There's very little support for dismantling state recognized marriage in this country, nor the legal invalidation of every marriage certificate. Nor any plausible path toward its implementation.
And if you want an individual contract that the State doesn't get involved in.....you have it. State Free marriage is already on the table for anyone that wants it. For those who want it, there is state sanctioned and protected marriage.
Sounds like a win-win to me.