I suspect a lot of Americans would tell you that a household income between $100,001 - $150,000 (two teachers, for example) is middle class. To put it another way, most households that made more than $100,000/year (in 2022 dollars) in 1967 were probably single worker households with a stay-at-home parent (mom). If both spouses are working to make the same amount, they don't likely have the same quality of life as a single-earner household would due to added expenses (especially related to childcare, but cost of commuting, stress on schedules, cost of home upkeep).