That happens to some. But when I was in High schoold and college I was a supermarket manager and the raise in minimum wage NEVER forced me to fire anyone. I may cut hours to make budget but they basically made the same money for less work and eventually they made more money as my budget was increased. So in the end they do make more money.
The greatest affects are in the smallest businesses, particular individual (one location) businesses where - as opposed to the large franchises and chains - there is considerably less chance for the increased cost differential to be diminished by increased sales volume.