I disagree with much of this.
As a child, we were middle class: 1960s: large detached house, pony, private school, tennis, ballet, theatre, foreign holidays (often two, in good hotels), daily, two cars, racing, mother had a p/t job admittedly, ate out at nice restaurants, probably once a month. We were very well off compared to others.
My children had a middle class upbringing in London: London day schools, sports clubs, large house, two cars, I was at home for the first 7/8 years and then worked through choice, home abroad, nice holidays, theatre, music, sport, two cars, holidays. We ate at a mid range restaurant for birthdays, special occasions. We never spaffed £125pw up the wall on pizza.
DH had a working class upbringing, possibly lower middle as his parents were a teacher and a engineer but wc roots. 3 bed semi, his sisters shared, one car which served 20 years, things rarely replaced, local comp, no foreign holidays, no eating out, no paid activities or small luxuries. They weren't skint but lived skint; most people didn't have the choice.
I think the op is describing a materialistic lifestyle which was livable when interest rates were low. Generations and generarions of people scrimped for enough on the table. There was a window when people had high expectations and plenty of disposable income but it was never going to last.