Two parents working doesn't matter when the environment is safe. When I was a kid both of my parents did work but I was walking alone/with friends to my school and back and didn't need to ask permission to go outside play with others. And mind you, that was a time when kid kidnapping was stil a thing. Imo what changed is abundance of cars- look how many ppl a killed by them, how big the cars got, how many spacy these take, look how far away is everything in suburbs- you basically need a car to meet with someone, it's even worse than a village due to the lack of a grid design. Also, because of spreading many third places became unprofitable, others were buldozed to create parkings esp in us with parking requirements. The zoning played a big role too- a lot of businesses that attract ppl, make the environment safer with social regulation and creating social bounds- can no longer be created bc of zoning. When tech did appear - it's natural ppl switched, bc these did offer more options to socialize safely compared to real world