Most restaurants in Europe generate an average of 250k in net cash flow per average restaurant, that's few years of work before ROI.
Not that I think McDonald's will ever really find themselves in a pinch, but if they did, they would additionally be able to liquidate selected properties for cash. When you are rich enough, the promise of having money in the future is just as good as actually having money. It doesn't work like that for most of us, but that's the nature of risk assessment in finance.