It must have been a whole different scene in the auto repair business back in the late 20s, when this photo was taken in Los Angeles. Automobiles needed so much more care and repairing than they do today. I am assuming, judging by some of the photos of elaborate repair shops and garages, that at the time there must have been good profits in larger cities.
It was also fairly common to keep your automobile in a local garage for storage, care and repair if you lived in a populated area and could afford to do so. You would call the garage and they would send a driver out with the car to your home who would be available to be at your service if needed. When you were done with the car, you would drop it off at the garage and they would clean, service and store it until your next journey.