OK, then how do people commute to their jobs (restaurants, shoe stores, or schools) in the small towns that support farms, mines, factories or mills?
Of course there are use-cases for cars, nobody suggested that there aren't. The problem is that the United States in particular has assumed that every transportation issue is best solved with cars.
There are studies showing that travel has actually gone down in areas like Mexico with the addition of modern Highways. The poor just can't participate.
More likely the poor used the highway once - to get out of the country and to the city. It isn't that they "can't participate", it's that they are gone.