I don't know how much I buy this. My wife is one of three kids. Their mom raised them for a while, while their dad worked as a teacher. Then their dad took some time off while their mom worked as a teacher. They're all well educated and, for the most part, well adjusted and they were all planned for - but based on your premise they were working -2 jobs while raising their family.
I'm thinking about my sister who, with her husband, is very well off. And yeah, I'm sure raising a kid as they know it takes a massive chunk out of their income - their kids want for pretty much nothing. But I also think there are ways to raise kids that aren't so detrimental.
I'm not trying to say kids aren't expensive, but I do think there's a bit of a fiscal boogeyman around kids, especially among the well educated.