No, see, that's just the thing. Th e state isn't interested in policing marriage; only incentivizing it. The state loses money on marriage so it darned well better be getting something in return. Historically, as well as now, the state gets the best formative envrironment for kids by setting the standard structure for marriage as "man/woman".The main thing is, we need a centralized, coercive authority in charge of our personal lives.
This is the worst kind of government. The state has no business "incentivizing" personal behavior in this way, regardless of the "returns".