Incorrect. McDonalds might calculate that for every hour someone sweeps in front of their store, they make $7 in profit. If someone is willing to do that for $6 an hour, they will pay. If minimum wage is $8 an hour, they will leave the dirt and leaves there.

That has nothing to do with having an economically viable business model.

Please do not engage on HN if you are unable to understand basic economics. This is not a place to argue something this trivial.