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.
