Wages tied to success of the company, ie profit sharing; how much more profitable could a restaurant become if every employee gives it their absolute best labor output? A few percentage points here and there? Certainly not orders of magnitude. Maybe theres no improvement in some situations at all? I don't see it as much of an incentive, especially if the variable compensation is partly in lieu of fixed compensation.

The startup scenario you mention offers the potential for huge payouts (of course this plays out wildly across a spectrum). A far easier sell to employees, IMO.