The issue in Atlanta is it has no geographic boundaries. My cousin bought a house 45 miles from downtown 30 years back because they could get an acre wooded lot and very nice house for not too much. He drives to work each day, gets up at 4:30 AM to miss traffic. But they have a nice affordable house in Dacula (real name).
I grew up about 12 miles out, dad drove downtown every day, back then we were on the outskirts of suburbia, had a half acre or so wooded lot with very private back yard.
And the State built more freeways of course and widened the existing ones to enable folks to live further out, for a time.
The usual story. Hard rail is just too expensive to expand. And some folks won't ride MARTA because there are people there who are not like them.