What was the average home size in 1970? What is the average home size today? Internet says that median house size in US went from 500sq feet to 907 sq feet. So yes, the consumption standards had risen significantly.
> These days, it's common for both parents to work
Can't say for US, but in EU these days it's common for parents to travel. It's common for parents to go on a massage or SPA on the weekends. It's common for parents to do sport, buy a bicycle etc. And I'm talking about regular blue collar peps.
My parents didn't do all that. They lived a much more humble life than most parents today. Also my mother did a shitload of manual work, she washed all the clothes manually, she did cleaning mostly manually, she fixed clothes with her own hands manually. How many times in the past ten years had you fixed your clothes with sewing?
So this "one parent was working" meant basically "another parent is doing a shitload of manual labor at home (because absent/more expensive goods and services) and they overall live a pretty humble life by today standards even adjusted for better services".
If you reduce your living standards to 1970s median, you can easily rise your kids with a single working parent. But neither you, nor your spouse and kids will like that standards of living.