It didn't "escape my notice" because IT IS FACTUALLY WRONG. The standard of living for the middle class is substantially higher than it was in the 1950s and even the 1970s (figures easily checked from the US Census Bureau). In exchange for the choice to have dual incomes, the middle class has substantially more living space/quality housing, more disposable assets, more cars and a higher standard of living (even econignoramus Elizabeth Warren concedes this). And, in fact, many (though nowhere near a majority) DO choose to live with a single income and STILL maintain a living standard higher than that of the 50s or 70s.
I don't NEED to make things up. I am fully versed with the easily verified data.