Right now 20% of women outearn their male partners and 30% earn the same. These numbers are only increasing in younger demographics where women are increasingly more likely to get higher education and therefore higher earning jobs. In 20 US cities, young women outearn men their age. To try to predict what things will look like 20 years from now based on the past is ill advised.

I don't think that two-earner families are going away anytime soon, but as of right now, the women least likely to marry are poor women.

The world is changing. Trying to cling to the norms of yesterday just doesn't make sense, particularly since they are the norms of about 4% of history.