You will never convince the SEIU and other unions of that. They love the $15 per hour minimum wage — even though it is a proved job killer. The unions love it because they get automatic pay raises every time the minimum wage goes up and the Donkey Party gets more union money laundered through the union’s dues paid by members. Then there are the dupes that really think a $15 per hour wage is owed them for working in no or low skill jobs. They can’t be persuaded until they either lose the jobs they have, get their hours cutback, their perks dropped, and their employer goes out of business.
Beyond what you describe, the government also gets a cut in terms of payroll and income taxes - basically passing more employer dollars through the employees right into government coffers...