When I was 20, people with kids put them in nursery so they could have holidays abroad and 2 cars. By the time I was 35, people needed two incomes to afford to maintain a really quite low-key lifestyle. Being a SAHP became something that people could only afford if they were on tax credits (as it was then) or one partner had a higher income. And the tax credit person would be scrimping!
Now, things are even worse. While £53K sounds a lot, in London and the south generally (I can’t speak for the other parts of the country) it won’t go far at all. And it’s true that renting is very insecure, especially if you’re on an ordinary income. I’m not sure I’d want that and have children. Where I live, on local FB groups I see people posting all the time that they’ve been given notice on their flat… they’ve got 8 weeks… 4 weeks… etc. Not all private rentals will accept children (even fewer take pets) and getting social housing is almost impossible. Were I doing it now, I don’t think I would. There’s climate change too, that’s a worry I don’t think I would want to impose on my dc if I were deciding again to have or not to have.