Job concentration predates the automobile by some amount. The concept of suburbs largely originates from the development of streetcars (very much not free!), although the suburban sprawl associated with US cities nowadays arises from the private automobiles. Note that streetcar suburbs are generally associated with medium-density development: it allowed urban centers to grow larger without having to really pack everyone into high-density tenements (though that still happened in many cases). White flight and the automobile means that post-WW2 suburbs become large low-density suburbs, focused on detached single-family homes.

In essence, the "unlimited free road consumption" created the disaggregation of decentralized, low-density suburban regions from the high-density commercial districts, which predates that concept by several decades.