I had the same thought but at the same time, population density can be desirable in itself and not just out of necessity. I'd definitely rather live in a dense city rather than in the desert country side.
I think that is very over-rated. Really nice cities with very urban environment don't actually have to be very dense, even if they feel like that.
And places that are very dense can still be worse then a US subburb in terms of feeling like a city.
One concept from a city planner said basically urbanism is not about density. Connectivity and access is what makes a good city, not density.
You can have a city with anywhere between 50k and 5M feel very livable and nice. And you can have a city with between 50k and 5M feel like a lonely place. Its all about the city design.
