The article tries to pin the phenomenon on high housing prices, Google, Twitter, etc but the numbers aren't really there. The big drop in the percent of families with children in SF happened between the 1970 and 1990 census. In 1970 24% of households had children, then 19% in 1980, 19% in 1990, and 19% and 16% in the subsequent decades. The share of children in the population had already fallen from 25% to 15% by 1990, and is down to 13% today.

All of that happened before software was even a thing in this region, when the major industries were defense and semiconductors. And it happened regardless of housing prices going up or down.