And from the other side, there are remote mountain towns in the Himalayas full of some of the kindest, most hospitable people ever. So perhaps being packed like sardines isn't an optimal human state.

I have to agree with the assertion. The political will to change anything decreases with the number of people in the area. It's hard to break compatibility between versions when you have a language used by almost everyone (javascript) vs when you are a new hippie lang.

China seems to be the only exception here with PRC having draconian control over everything.

'Population Density' is a civic function, not some random variable.

Like many things, it's a random variable when there is no civic function, but once it exists, then it's part of 'planning' aka 'generating wealth' in whatever terms that means for a group of people.

How does a township with 50% unemployment also have garbage lying about everywhere? The marginal cost of employing people to at least collect is minimal. A town with 50% unemployment is extremely rich in excess labour capacity, they should be able to hire people cheaply.'

Why not? Because social organization is probably abysmal.