In a big city with rising rents, people who already live somewhere ~have a right to be there~ and shouldn't have to go. In a small town, apparently, there's no possible reason people would want to stay.
One of the things we currently do, through differential housing prices, is send retirees to small towns with dead economies. They get a pension, Social Security, and Medicare, and that income is often the sole thing keeping the town afloat. In more distant reaches (I'm thinking Appalachia and parts of the South), generous welfare policies have enabled people to stay in this excess housing capacity despite the lack of jobs.
But here's the thing - there are costs to this strategy, like greenhouse gasses and children/grandchildren that have to move away and human capital going to waste, and these people could just as easily have public services provided in a metropolitan area where it's much cheaper to reach them all and provide a good quality of life.
The phenomena shows up even at the state level - https://img.washingtonpost.com/wp-apps/imrs.php?src=https://... but it's much more stark when you start at an older town in the Eastern half of the country and make your way to a productive population center.
Hey, we have a fiscal union, unlike the EU; These places aren't Greece because of all those payments, and I don't support turning them into Greece, but because we have that union it's also on us to make deliberate decisions that concentrate less of the population in Stavrodromi and more in Berlin. The game-theoretically natural strategy of utilizing the entirety of the existing housing stock (stratified by income) no matter how decrepit the location, is a bit of a local optima, and better arrangements are not difficult.
It'd be interesting to see if perhaps it's better for the feds if they're in rural towns but not the states.
In Albany, NY where I'm from I used to live right near a major hospital and college Albany Medical Center. And there were helicopters flying to it three or four times a day. I'm sure some of those helicopter rides out to taxi those requiring medical assistance are being borne by tax payers. It's a pretty complex question to wrap your head around when there are so many variables. Does an elderly person living in NYC produce a small drag on the economy because they're not contributing as much as the average young professional and increase the cost of rent for those people?
We really have much bigger social problems than insufficient subsidies to people who choose of their own volition to live in places which are expensive for everyone else to maintain.
Not that this has too much direct impact on roads, though :P
Rent control causes landlords to fail to realize hypothetical profits; government-subsidized sprawl wastes everyone's money.
Lots of small towns are nice and scenic. Lots of other ones are vestigial organs of some long forgotten economy and would better disappear.