We're talking about a potential utopia where education is available to everyone, not restricted to first world countries. If you bring everyone UP to western world QOL and they are educated, you have to consider it in that aspect.

The immigrant fertility rate thing is because they come from a place with low expected QOL so they don't think they need the american dream with air conditioning, going out to eat or having nice things and instead go with more kids because they were raised that way. The second generation gets used to say american QOL and wants to have those same nice things the neighbors have- after all they grow up in the american school system meeting other kids right?... so you need to work to get those high QOL things and suddenly you're in the situation I have described: needing more professional attainment to keep up the expected QOL and delaying children.

Does that make sense?

Do you have any kind of evidence showing that free of all financial constraints people will not have children in a mid-high COL area?