In some religious groups, marriage prep is mandatory. I also think some sort of marriage prep, either tailored to the couple's religion or purely secular, should be required for everyone hoping to marry. In times and places where everyone was brought up with the same understanding of marriage as a lifelong commitment to fully love each other, marriage prep may have been less of a necessity. (A couple I know who eloped is one of the cutest success stories I know of, but they were married in the early 1950's, and no-fault divorce was not on the table for them.)
It's also far easier to be successful in marriage than it is to win the Nobel Prize. In the US, about half of married couples stay married for life. (Rather proving my point that marriages only fail because people fail at marriages, the risk of second marriages ending in divorce is greater than the risk of first marriages. The more divorces a person has, the more likely they are to divorce again.) But people's chance of winning a Nobel Prize in any field is far less than the chance of succeeding at marriage.
Also, anecdotal evidence is just that, but my husband's parents divorced. And while I like my husband's stepmother very much, I can't say the divorce and all that led up to it did no damage to my husband's family.
I also know just how entwined a couple's life can become, even when they're on equal financial footing, especially when things like shared credit, home ownership, and children come into the picture. In a lot of cases, divorce can cause more problems than staying together. And if a couple loves each other enough to not wish to subject each other to that kind of stress, that's a good enough reason to stay together.