It bodes poorly for the environment if people are increasingly moving from denser cities to sprawling suburbs. This is in many ways a self-inflicted problem of high-cost cities, but it should be a national priority to reverse this trend.
It's always crazy to hear that suburbs are cheaper. Dense living inherently requires less infrastructure and less transportation, so it should be considerably cheaper. It's only through the subsidisation of suburbia and the low supply/high demand of high density urban areas that this is the case. Car centric suburbs aren't just terrible for the environment, terrible for safety and terrible for transportation; they're…
Low supply due to underbuilding.
High costs due to difficulty in getting housing approved and forced BMR units.
More expensive land price.
Not needing to own a car saves you money.
And, most importantly, proximity to jobs and services. Living in a dense urban area saves you the time of driving and commuting, and has more amenities, restaurants, and things to do within a given X minutes. Buying time is expensive and a luxury good. This is where a lot of the demand comes from.
The problem is not just subsidization. Urban (especially “ultra-urban” in dense areas like Manhattan, non-suburban SF, central Boston or DC, Brickell, etc) residences have low supply and high demand.