The funny thing is that it was Nixon/Reagan economic policies that destroyed the one income family.
LBJ wanted a quick win in Vietnam; when he realized he was stuck in a quagmire he started paying for the War by printing money. Nixon ran as a peace candidate who would control Johnson's inflation. Instead he doubled down on both policies [more bombs paid for with paper money]. By the time the Arab Oil boycott was in full effect a lot of middle class women found they had to go to work in order to keep the household going.
Jimmy Carter hired a man named Paul Volker to try and control inflation. Carter's policy worked, but Jimmy had been voted out before people saw the results.
Reagan kept Volker but created his own inflation by cutting taxes and spending more than ever.
In 1968, 'middle class' was defined as one income supporting a family of four. In those days $1 million was considered a vast fortune.
By 1992, when George Bush Sr was done, 'middle class' was two incomes and $1 million was what a richguy paid for a party.