This has been well know for a long time. However the fact is the only reason that McDonalds is able to collect rent (in the dollar amount that they do) is if their product and service, the franchise, is able to sell hamburgers to customers. As such the value of the real estate (if the franchise fails to operate) is nowhere near what it is with a profitable operating restaurant. While the locations are valuable if you have ever seen a vacant McDonalds, and who typically rents those, you will know that the rent received and royalties is nowhere near what it is with a McDonalds restaurant.

So I think it's a bit misleading and hyperbole to say 'how they really make money'. The only reason the can make that money is because of the product and the customer base that patronizes the McDonalds. So in the end it is because of the product. "How they really make their money" is because of that product.