Plus, whether people like it or not, a married couple is still a family, even if they don't have children. And they still get almost every incentive of marriage whether they are able to or even want to have children, and that doesn't change if they never have children. The only ones they could be considered not to get, they wouldn't need since they would pertain directly to access to children/child care for children they don't have.
Marriage is never going back to "for the raising of children" because the majority doesn't want it to. The majority wants people to marry for themselves, instead of the children because it is better to ensure the couple is happy with each other whether they have children or not than to force the couple together or to stay together for the children which leads to unhappy, dysfunctional families. Blame it on women's rights and liberation and in the work force if you wish but it isn't returning to what it once was so the best thing to do is to adapt to what it is.