We’ve never had more pampered living conditions.
If the only economy in which people decide to have kids is the rarefied air of America in the 1950s when min wage could afford a home, then that’s far too narrow of living conditions for a species to propagate.
The reality is humans have always been costly, but people had them anyways for unintended + cultural reasons. When you have a child, they’re a massive productivity loss for 5+ years, so even subsistence farmer humans or hunter gatherer humans found them incredibly costly.
And the people today making great salaries in major cities could easily afford multiple kids while still being comfortable, but their lifestyle would be more modest than otherwise. People far poorer have far more children.
I could personally afford kids and I’m slightly above median household income as my wife is starting her own business. I don’t have them though, because there’s more I want to push to accomplish. That’s a very common sentiment, and it’s more to do with cultural priorities than economics.