Nah, it's because the franchisees pay for every cost. McDonalds leases the land for them and collects the franchise fees, royalties. It's essentially free money for the company.

When they operate the restaurants there is costs of buying the ingredients, paying the employees etc. And the revenue comes from the burger sales.

On the franchise part the revenue is from the fees, so of course there's not much cost to that. I don't think the burger sales from the franchises even show up on the income statement, that's the franchisees revenue, not the company's