Most systems that modern city people rely on are not thought out to maximize well being, but social control. To limit human potential to what is possible under such circumstances is a mistake. We could have so much more. But capitalism... That is the real limit we are living under.
Malthusian myths about how many people can live and thrive on this planet are just neo-eugenics. No matter how many material facts or scientific projections they try throwing in the myth. That such myths are still popular amongst some circles is just a tell on how fucked up those social scenes are. like Academia and Western self proclaimed elites.