These clowns don’t work there to begin with.
Food is price-sensitive. Food franchises operate on a very small profit margin.
To pay unskilled workers $15 an hour something has to give - either hire them part-time or raise the price of food.
No manager is going to price their restaurant out of business so the employees will have to work fewer hours.
Which means they’d make the same amount part-time as they did working full-time! Nice way to price yourself out of a job!