That can always be an argument. You could place all humans in Great Britain easily. Would perhaps be more productive as well. Imagine all the biotopes that could strive again. But it isn't a question about productivity and I believe the vast majority live in high density setups for utility. At least I do. It is nice enough but it remains a compromise.

Not from the US, but expect this story about high density areas paying for the others is a stupendous political argument to get people angry at those suburbians and not too much else. The distribution of funds is probably unjust, but the solution is certainly not to bring everyone into high density living.