> And supporting a whole family on a single income well was a very narrow window of time, and it required the US to have no real economic competitors.

But then how were other countries able to have this while having economic competitors?

Some places relied on other ways to make money (here in Australia it was comodoties). A lot is just social change to two income households, and it's main contributor to living costs was housings. Two people bringing in money ,means that households can pay more for a mortgage or rent, driving up costs.

That's what drove up housing costs after we switched from single to double income households. But before that, but before that, people in lots of countries could afford a house and a family on a single income, despite competition from other countries.

It's not that this situation was unsustainable or only attainable for the US; this situation should have been the norm, with the additional income just providing extra luxury or time off, but instead we got screwed through artificial scarcity and more money going to the very rich instead of the working and middle class.

A lot of this is just social change from the womens liberation movement. Women went to work and the market adapted. Now, in the main, you need 2 incomes to run a home.

It's worse in a lot of countries where tax policy disadvantages the pre-1960 norm like the UK.