Stephanie Coontz writes,

In 2001, University of Texas psychologist David M. Buss and colleagues compared mate preferences based on national surveys taken for several decades beginning in 1939. Their research, published in the Journal of Marriage and Family, found that in 1956, education and intelligence ranked 11th among the things men desired in a mate. The respondents were more attracted to someone who was a good cook and housekeeper, had a pleasing disposition, and was refined and neat. By 1967, education and intelligence had moved up only one place, to number 10, and still counted for less than being a good cook or displaying neatness and refinement.

…in mate-preference surveys taken in 1985 and 1996, intelligence and education had moved up to number 5 on men’s list of desirable qualities in a mate in both surveys, ahead of good looks. Meanwhile, the desire for a good cook and housekeeper had dropped to 14th place in both surveys, near the bottom of the 18-point scale. And in choosing a spouse, males with a college degree rate good looks much lower in importance than do high school graduates.

…Furthermore, college-educated couples have lower divorce rates than any other educational group. And in the last 30 years, while the marriages of less-educated women became less stable, the marriages of college-educated women became more stable.

If you ask me to predict economic inequality, my expectation is that it will rise. These trends in assortive mating and relative marital stability are the reason.