Well, then McDonalds can offer more money to work there. Obviously, McDonalds wants to stay in business, so it has to offer up some incentive to get people to work for them. If they offer enough money, there will certainly be people who would work to flip burgers.

The jobs' salaries match what they are actually worth, and can't be offered as minimum-wage jobs that people take because they don't have any money and can't get a job elsewhere.