As recently at 1970 a small town would have one fifth of the store fronts related to auto sales and services. Tire sales, auto sales, gasoline stations with repair shops, stand alone repair shops, insurance, auto finance offices, auto parts stores, glass and upholstery stores. Plus the trucking businesses that served all the auto related stores.
By the mid 1970s the stores and offices started to disappear. Today, I would estimate that less than one 10th of the small town main street businesses are related to autos.
This change is due partially to improved tires but mostly due to the high quality of Japanese cars. The invisible but powerful march of Toyota and Honda across the U.S. left a large swath of open store fronts and vacant offices on main street that formerly serviced poorly design autos.