I have to wonder on your hypothesis: Do they vote Dem *because* they are packed in so tightly, or do they live like that because liberals are drawn to that kind of environment? I believe it’s the latter.
I think its a bit of both. But with young people striking out on their own, they tend to be drawn to the cities by the excitement and social life aspects of it.
Probaby some of both. There is a certain percentage that flee the big city when they have the money or opportunity.
I believe it is the former. Humans are apex predators. The higher the density, the less freedom and the more rules are required to make it work.
then they all vote democrat.
there ARE rich democrats, but mostly in power centers like state capitals and ny city and LA and the like
but in rural America most ‘rich’ areas are republican, and most rural middle income areas are a mix but trend republican