Cost : Benefit.
Many people want to live in cities and are willing to put up with the costs. Also, living in a rural area has hidden costs. For example, you’d have to spend a lot more time on the road if you lived out in the sticks. You’d need a generator in case power went out, etc etc.
That’s not even getting into things like schools and hospitals. People in Vermont/Wyoming routinely have to leave the state for top notch medical treatment.