Except that we didn't work to maintain what we had. Education systems were gutted, public infrastructure was sold off to the highest bidder (Bayh-Dole act, every privatization of government services that followed), maintenance was deferrred (many roads and bridges are deteriorating in both Europe and the USA, 80% of nuclear plants in operation today will reach EOL in roughly ten years without replacement).

Yes, periods of prolonged prosperity aren't unique, and they always end in one of two ways: destruction or decadence. Take your pick.

for almost a hundred years we've seen each generation get wealthier

This isn't true. The last generation to be wealthier than their parents were the baby boomers: https://www.visualcapitalist.com/charting-the-growing-genera... . The average wealth per person has been decimated since then: Generation X is only half as wealthy as baby boomers, while the average millennial is ten times less wealthy than a boomer. And this isn't just because of their current age:

> In 1989, Baby Boomers and Generation X under 40 accounted for 13% of household wealth, compared to just 5.9% for Millennials and Generation Z under 40 in 2020.

So in 30 years time, the younger generation lost over half its wealth to the older generation.