The Speedee Service System, not the hamburger, was the invention
In 1948 two brothers threw out most of their menu and rebuilt the kitchen as a production line. Everything else followed from that.
historyoperationsThe McDonald brothers were already running a successful drive-in when they closed it in 1948. The problem was not demand. It was that a long menu, carhops, crockery and made-to-order cooking made service slow, staffing expensive and quality inconsistent.
Nine items
They reopened with a menu of nine items, no carhops and no reusable tableware. Each station in the kitchen did one thing. Grill operators did not dress burgers; the person dressing burgers did not take money.
This is a manufacturing idea applied to food service, and it is the part that was genuinely new. The hamburger was not new. The delivery of a consistent hamburger in under a minute, by staff who could be trained in a day, was.
Why it franchised so well
A system built on fixed procedures rather than cooking skill can be copied. That is what made the chain expandable, and it is why the same logic now shows up in businesses that sell nothing like food.