This entire discussion is about laws regarding minimum wage, the act of literally making it illegal to hire for less than a certain wage. I’m not sure I see the confusion
Wages are a cost to a company. There are other costs to a company. Companies also return a profit to the owners. If a company's costs are too high, they my not return a profit; they may not be able to pay their creditors.
My dad ran his own very small business. I am familiar with a business not making a profit for a period of time. I am familiar with workers who are not profitable to employ.
It is a reduction to absurdity to state that minimum wage "makes it illegal to work unless you can produce $X value per hour."
There are interesting, non-absurd discussions about the effects of minimum wage, but this is not one of them.
The number of employers seeking such an arrangement is so small it's irrelevant. In practice, not being able to pay people less that $15/hour means you won't hire people who bring less that $15/hour of value.