I have seen far too many people get married for reasons that are rather immature:
1) Being in love (illusion)
2) Having found my soul mate (another romantic notion)
3) They just complete me (incomplete people don't become whole through marriage)
4) Programming or societal pressure (everyone else is doing it)
There are no do overs in this situation. Young people are most often (not always mind you) not developed enough at an earlier age to do the marriage and parenting thing. There are some that are capable of putting it together emotionally but there are other details around life that have to be accounted for as well.
I have seen far too many people get married for reasons that are rather immature:
&&
I have seen people in their 30s & 40s marry for the same reasons you cite.
I guess we will just have to agree to disagree on this one.