What is the Speedee Service System? Who invented it and does it work?

From the text:

The McDonald brothers’ Speedee Service System revolutionized the restaurant business. An ad of theirs seeking franchisees later spelled out the benefits of the system: “Imagine — No Carhops — No Waitresses — No Dishwashers — No Bus Boys — The McDonald’s System is Self-Service!”

It was designed to increase the speed, lower prices, and raise the volume of sales. The brothers eliminated almost two-thirds of the items on their old menu. They got rid of everything that had to be eaten with a knife, spoon, or fork. The only sandwiches now sold were hamburgers or cheeseburgers. The brothers got rid of their dishes and glassware, replacing them with paper cups, paper bags, and paper plates. They divided the food preparation into separate tasks performed by different workers. To fill a typical order, one person grilled the hamburger; another “dressed” and wrapped it; another prepared the milk shake; another made the fries; and another worked the counter. For the first time, the guiding principles of a factory assembly line were applied to a commercial kitchen.

The Speedee Service System, however, got off to a rocky start. Customers pulled up to the restaurant and honked their horns, wondering what had happened to the carhops, still expecting to be served. People were not yet accustomed to waiting in line and getting their own food.