Higher population density in urban areas severely reduces the need for cars. It's possible to live in cities developed pre-car (London, Berlin, Boston, New York) without owning a car. Americans have put ourselves in a pickle by building sprawling suburbs, which then require cars to increase the "number of highly specialized people" they can interact with.

There are however many people who find high-density living to be unappealing

That, and they drastically reduce housing costs, and increase incomes. Two of the biggest areas we're currently sliding backwards with in modern cities.