I think this nails it on the head. The writer is conflating the affects due to socioeconomic conditions with the affects he wishes to perceive as it strengthens the arguments he brought forth in prior essays. This seems like an exercise of mental gymnastics as marriage age and birth rate have been pretty correlated with the cost of living throughout the world. When I left London during its peak costs, the average age for marriage was 36 for me and 32 for women. The displaced rural American worker clinged to both Sanders and Trump in the last primary. This isn’t some massive conspiracy. Home owners in SF and NYC have discouraged development through NIMBYism. Meanwhile, magnetic schools and private school options haven’t really grown their pupil base. If you are making a million a year, the equation works out, but if not, you need to make sacrifices, and, for many millennials that means sacrificing reproduction over lifestyle.