Here's a very brief rundown of how the GOP destroyed the middle class.

LBJ thought he could win the Vietnam War with a massive push. Instead he got caught in a quagmire. He was paying a lot and decided to print money instead of raising taxes. Inflation begins to creep in. Nixon gets elected as a 'peace candidate.' Dick triples down on LBJ's policy. Not only does inflation increase, ramping up steel production to make tons of bombs means that the Japanese and Germans have to build their own steel mills. When the Arab Oil Boycott hits, US auto makers find that they are losing to foreign competition for the first time ever.

Jimmy Carter is elected. He solves the inflation problem by hiring Paul Volker to run the Fed. Carter loses to Reagan, who keeps Volker and takes credit for the win. But Reagan has his own plan. He cuts taxes for the rich and starts borrowing money to pay for the government. He also lets the Saving and Loan banks make billions of idiot loans with the full backing of the FDIC. [Look up Presidential son, Neil Bush and the Silverado Bank for details.]

The tl, dr is that in 1968 'middle class' was one income paying for a family of four and $1 million was considered a vast fortune. By 1992, 'middle class' was two incomes and $1 million was what a rich guy paid for a party.