Ray Kroc said, "McDonald's is not in the hamburger business but in the real estate business." How?

[thebuffettour]

I'm not completely sure about this. I know some stores who build shopping strips and have their store as the anchor store but make their real money on the rentals of the other stores but McDonald's are usually stand alone stores. Does he mean that it is now about the burgers but how convenient it is to get the burgers?