If a business requires someone to spend 40 hours a week doing something, but cannot afford to pay them a living wage then that business should close. They are a failure and should get out of the way so that a competent business owner can replace them. Worker exploitation should not be keeping failed businesses afloat. Starbucks does not have this problem. They're just exploiting workers to stuff their own pockets and could easily ensure that their employees are all able to afford to live on their wages.
There was a time, not very long ago, when a single person could support themselves and a family on their wages. Paying a full time employee so little that they can't even support themselves should be illegal.
All this "think of the children" nonsense ignores the fact that most jobs paying minimum wage are not held by children, and that most kids don't need full time hours (and arguably shouldn't work that long anyway since they have school) and anyone, even someone in an entry level position, still absolutely deserves a living wage for their time.