An overview of some booming American exurbs explains why they are growing:

Exurbs are areas typically located 40 to 60 miles from city centers and are often appealing to families seeking more space, affordable homes and a quieter way of life.

The trend has transformed once-sleepy rural towns into thriving cultural communities with booming populations and housing markets…

The COVID-19 pandemic has played a significant role in the shift to the exurbs, with many people now able to make a living from home thanks to an increase in remote work opportunities. 

This means they are no longer tied to big hubs where offices are based.  

Skyrocketing housing costs in major cities have also pushed many families to seek more affordable and spacious alternatives.

Finding affordable housing is a significant issue across American metropolitan areas. The thought often goes that the further one moves out from the center the more house a buyer can get. (This can ignore the pockets of cheaper housing that do often exist closer to the center of regions but the assumption is those who want these cheaper homes also want a particular kind of suburban community or way of life.)

But there is another component to the growth of exurbs and the suburban fringe. There are jobs and other economic opportunities on the edge of regions. Commuting to the big city is arduous from these far-out locations. The article above hints at the possibilities of working from home but numerous exurbs grew before this. Where are people working?

They are often working at companies and organizations in the suburbs. If I live 60 miles outside the big city, I may commute to a job 45 miles from the big city. Those edge cities spread throughout regions can provide thousands of good jobs accessible to those living in the exurbs. Or the new growth generates jobs and opportunities in the exurbs. Yes, some people can work from home but these are particular kinds of jobs and new growth leads to medical jobs, service jobs, and jobs in other industries that also find it attractive to locate in exurbs.

In other words, you cannot have the cheaper housing of the exurbs without also having jobs and opportunities in and near the exurbs.