Yeah, that only the wealthy can and should have children is of course a point that is hard to sell and not quite politically correct.
As I don't like labels like "political correctness" either, I'm going to try for a more rational argumentation:
Some say a radical free market would result in slums on the one side, and gated communities and glassy skyscrapers on the other side of the city.
If there is some truth to this or not, I believe a society with insufficient equality will not reach and realize its full potential. Obviously, if children in the slums never get proper education, they won't be able to properly contribute to the society or economy later, even if they wanted. Hence there is a loss of resources.
If there was an experiment of setting up city states, some radical libertarian, some with a social tax (also compensating for maternity), I'd predict the latter will therefore create a higher standard of living, a better social climate, less crime, and more wealth.
What does it mean? There's a saying that people get the government they deserve. Maybe we still have to mature a bit before we deserve to get rid of it.