I think having both the companies owned by the same people would come under quick scrutiny, and the companies would quickly move to finding someone to pay for a

I think having both the companies owned by the same people would come under quick scrutiny, and the companies would quickly move to finding someone to pay for a "service" for all their low-paid worker needs. So you'd end up with Burger Corp being executives like you said, and then hiring Service Company X to do all their cashiering and burger-flipping and janitorial services. They'd be owned by completely different people, and Service Company X might even service multiple companies much like many temp staffing agencies today. Attempting to stop this would also kill most existing janitorial services among other things, and it'd be really hard to regulate. In the end, things move around, but they don't really change.