Sociologically, as fewer couples have large families, and more women are capable of supporting themselves, it is less necessary for survival.
Sociologically, as people live much longer lives, making a lifetime commitment to one person is more difficult.
What this means is that if marriage is to survive, couples need support. They need to learn how to communicate well, to compromise, to support one another and accept one another unconditionally.
Coercion (pressuring women to have large families or discriminating against them in the workplace) isn't a good way to encourage marriage. Although it certainly worked for several millenia, it denies women's human rights.
Certainly tax and government incentives promoting marriage are good.
I've said before, a lot of Catholics do handstands (ending in standing ovations) praising unwed mothers to the skies for not having abortions without ever saying, "Why not get married?" or "It might be a good idea to get married." So fearful are they that if they don't put an unwed mother on a high pedestal she will have an abortion that they don't try to encourage her to do something which would give the child a more stable life.
When I had my first child at 26, my mother's good friend's daughter (21) had hers.
I had been married 5 years. I'd owned a house for 2. Both my husband and I had gotten our college degrees (his at night school, resulting in his graduation one month before the baby was born).
She refused to marry the biological father (didn't love him) and proceeded to marry an itinerant musician, several years later, who had a groupie in every venue. Eventually, of course, they divorced, too.
I am not saying she should not have received compassion....it was just the "canonization" that bugged me...
She wasn't a saint. She was someone who compounded one foolish decision with another...the really kind would have told her, "You're a parent now. You don't marry an itinerant musician with groupies in every venue. You marry someone who will be a good husband and father." Why didn't anyone tell her that?