I think it's hard for us as individuals to understand the scale of McDonald's. They claim that 1 in 8 people in America have worked at McDonald's... that's... INSANE!
Sorry, not giving McDonald's a pass. They have a large team of data scientists and technologists working on their app and customer data. Even with a massive base, running a query to find individuals whose spend has dropped 50% y-o-y is not too difficult, and should be an urgent priority at a company that reported "negative comparable guest counts" (i.e. fewer customers y-o-y) for fiscal 2024.