One writer suggests the sprawl of the Sun Belt leads to significant costs down the road:

Over time, growth has reduced those advantages. Jobs and people moving to states like Texas and Georgia slowly bid up the price of land and labor. Ample spare capacity for land and transportation infrastructure — think six-lane highways — let sprawl be a growth outlet for decades, but over time congestion and distance from airports and job centers raised the cost of sprawl as well. The 2008 financial crisis arguably busted the sprawl model in the largest Sun Belt metros of Houston, Dallas and Atlanta, where until the onset of the pandemic single-family building permits had lapsed to 35% below the 2006 highs, despite those metros still having reputations for sprawl and fast growth…
What’s needed to maintain past growth momentum and meet the expectations of these new populations is a continued push up the value chain towards local economies based on knowledge work, with higher-paying jobs and college-educated workers. The specific services or investments needed to lure these types of jobs and workers will shift with the political winds — it might be a greater investment in schools and universal pre-K programs today, and transportation infrastructure tomorrow. It’s the same kind of policy arms race these communities have been accustomed to for decades, only with more services replacing low taxes as the policy lever.
For now, the most likely tweaks to the governance model will probably be incremental — stormwater improvements, sidewalk construction and other “complete streets” projects, modest increases to educational funding — simply because the votes aren’t there to raise taxes enough for the kind of revenue needed for bigger changes.
But these tensions aren’t going away. It’s eventually going to require larger investments than current leaders and older voters are willing to make. Ultimately, the choice for these communities is to spend the money needed to stay competitive in the new arms race, or lose out to places that will.
In the United States, growth is good. Communities need to grow to show that they are exciting, thriving places. New residents and businesses signal good things to come.
But, the piece quoted above notes the longer-term possibilities of such growth. What happens after the fast growth slows or ends? Is it sustainable? How do communities switch from fast growth to mature growth or stability? My own research in the Chicago suburbs suggests this is not necessarily an easy switch. When the land starts to or does run out, communities have to make important decisions. Should they grow through increased density and/or allow taller buildings? How much will it cost to maintain all of the existing infrastructure? How much redevelopment or teardowns will take place? Even during the high growth periods, the costs can increase – see battles within sprawl over the costs for new schools and who pays – let alone as the sprawling areas age.
More broadly, what happens to sprawling suburbs decades after the sprawl has ended? We can now look back at numerous postwar suburbs and see what happened. The Levittowns always draw some attention for the ways they changed and are still the same. Many of these suburbs are over a half century old (though others are newer). These communities revolve around single-family homes and driving, among other things, and this might continue for decades. Or, it might not if conditions and ideologies change.