1. Millions of women entered the workforce (started when all the men were overseas fighting)
2. The government went off the gold standard
3. Millions of people in other countries replaced the workforce via globalization
Those are the three biggies. Expanding the number of available workers kicked off the pressure on wages. Going off the gold standard kicked off massive inflation. Globalization shrunk the number of jobs available and was the nail in the coffin.
So that's why we don't have the same economics as a nuclear family in the 60s.
Now in practice a lot of essentials in the US CPI have stayed pretty cheap. Technology enabled a lot of things to stay or become cheap. But a few big ones are a train wreck. Home ownership, health care, education, all skyrocketed.
So when I see someone on the median income say "Man I'm getting older and I don't know how you can afford to settle down and buy a house and start a family" yeah that's a very real problem which is grounded in facts.
But when someone says "life sucks for the 24 year old who has the resume to work in the Valley and pulls down almost a quarter mil," here's what that is: horse shit.