Jesus christ you haven`t learned anything have you, it was entirely financed by credit.
Lower and middle class earnings growth has not exceeded the rise in inflation in 40 years, furthermore, lower and middle class buying power for actual wages earned not including credit purchases has not increased in as many years as well.
Sure, you can buy more stuff, but rather than being on one income, families now have 2 incomes, credit card debt, and home equity loans which is what got the USA into this mess to start off with! What are you going to do now, put the kids to work
The difference between now and 40 years ago was that a) credit cards were not prominently used b) there were really no home equity loans and c) people did not carry heavy mortgages on overinflated properties, oh and d) the USA wasn`t laden with debt and interest payments to the same degree.
By the way sorry there are no question marks in there, my keyboard is messed up.