Dual income earners hasn't even increased that much, 44% in 1967 to 53% in 2011 - https://www.bls.gov/opub/ted/2014/ted_20140602.htm

Yeah I think there's this fictional idea that families in the past didn't struggle with money and need both parents to work. My father worked full time and my mother worked about 30 hours a week when I was a child (1970s).