Don't minimum wage people purchase slot of fast food? Wouldn't a minimum wage hike lead to increased sales to offset the hike?

I repair alot of I. T. At many major chains so I visit them regulary. They seem pretty efficient and an extra $20 an hour of labor costs doesn't seem like a game changer. Especially if it reduces turn over or improves employee moral. Would definitely hurt something like a stake n shake.. 24/7 operation and tons of kids.