Actually, there are many ways Employers can get around retaining their current level of employees. Not replacing those who retire or voluntarily resign, or replacing them with robots, or hiring Part Time workers who do not receive benefits the same as Full Time employees.
Sometimes this reduction is necessary for the Employer to just stay in business. The rising costs of Health Care is one of the greatest burdens on Employers, and they simply can not afford to pay the cost. So, they have to reduce their staff, and do the best they can to continue to provide the service they provide to the public.
Even the Government is doing this. When I go to the VA, I check in on a Kiosk. Kiosks have replaced people, and saves the Government/VA money. Now, they do still have real people there, but not nearly as many as they once had, or not nearly enough to provide the quality of service they used to provide.
Minimum wage jobs were never intended to be a life time job. They were designed to be "entry level" positions to allow young people, or people with no experience gain valuable experience that would allow them to advance within whatever Company they are working for. The simple truth is, the higher the minimum wage, the fewer employees most Employers can afford to employ.