I think it was the Reagan administration made credit card debt interest tax-deductible and the cat was out of the bag.
Of course, China's rapid rise in personal as well as private and public sector debt is evidence of a changing society.
While that is a lot of debt, it is nowhere the same as saying you have $500k of debt on credit cards. Credit cards are unsecured debt; it's debt with little or nothing behind it.
Mortgage debt, though, is a secured debt. In theory, you could sell the houses, maybe for more than you paid for them, and possibly or likely more than you owe on them (that is, you gain the equity). Of course, you could also be upside down, but you still have the property, and you could just sit on it, rent it out, and continue to make payments on it from rent (or whatever) until the market comes back.
Traditionally China is known as a nation where people save, and debt was not seen favorably at all.
This is a cultural thing, which has likely been wearing out since the 1990s.