@kimberlymacg I agree that the attitude you describe exists and is very common, but it’s nowhere near universal, or even a majority approach among high-achievement kids. (Among non-high-achievement kids, it is not at all common.)
Outside of New York and San Francisco, hardly any of the young people I know who are interested in marriage waited until their 30s to find a partner. When I look at my children and their close friends, I see a whole bunch of people getting married at 29 or 30 to people with whom they have been involved for a number of years. I can count at least six cases of married couples who met in college (although in some cases, including that of my son, they did not become romantically involved until after college), and two couples where the people met in high school or middle school and reconnected shortly after college.