They won't, though. Because these are cost-saving tools for multi-nationals with enormous capital footprints.
McDonalds isn't going anywhere, no matter how bad their hiring practices get. The only real risk they run is in their poor ability to bring people on quickly resulting in storefronts more vulnerable to unionization or other labor actions. But this is a business that's been vertically integrated for decades and subsists on enormous direct and indirect subsidies from every layer of government. They'll keep being fine unless the political conditions in this country change significantly.