To understand what is really going on, you have to understand the union exemption.
Non-union companies have to pay $15/hour. Union companies can pay less.
Be that as it may, the union contracts are directly tied to the minimum wage. This is a benefit that is already baked into the cake.
Do you think the unions and the $15/hr crowd are going to care when a company like “Momentum Machines” can make a burger to order every 10 seconds, and not just assist workers but displace them completely.