I'm 51 and I grew up by surrounded by women who didn't work full time. We were a completely average family in a very ordinary working class street ih the north west of England, new build (for the 70s) 3 bed semi. Many women in the street were SAHMs with husbands with normal jobs. Some of them worked cleaning jobs eg in the local school, to bring in extra money, or in the local shop, while their neighbours minded their kids free of charge. A few women had more professional jobs like nursing however I didn't know any of them who worked full time when their children were below teenage ages. There just wasn't the childcare system in place to do that.
I knew women who were more middle class than in my road. None of them worked either - their husbands' salary was enough for everyone. Some of them even had au pairs. I also knew women who were more working class. It totally depended what their husbands did/earned as to whether they would need to work. The only women I knew who had full time jobs did it out of necessity, because they were divorced and raising the kids alone. It was just expected that when you got pregnant you just left work when you had the baby.
DH grew up in a ver working class area, rows of terraced streets. His dad had jobs like mechanic, or foreman in a warehouse. His mum only worked part time in basic jobs. The rest of the street were very similar. The only woman i know working FT in around 1980 lived in London, didn't have any kids, and worked in a department store.
I've no doubt that a few kids were latch key kids with both parents working fulll time, but as I said, it was highly unusual. I find that a lot of older women tend to say "I've worked all my life" or "I've always worked." When actually many of them don't actually mean full time (once they had kids anyway)