It’s apparently cheaper to keep waiters than busboys due to a bizarre labor-law loophole.
In many states, it’s cheaper to keep servers on the clock than bussers because of a loophole that allows restaurants to pay servers who earn tips less than the minimum wage — as little as $2.13 an hour. Bussers must be paid at least $6.55 an hour.
https://www.businessinsider.com/2009/1/busboys-cleared-away-to-cut-costs