I’d say it’s mainly due to the fact that most didn’t have to pay for childcare ( grandparents, aunts, cousins, or older siblings babysat or mom was a stay at home mom). they didn’t have crippling student loan debt because college was affordable up until the late 90s/early 2000s or they didn’t even attend college. Homes were also more affordable, as were groceries. Also, cars were significantly cheaper as was gas and insurance.