"If you pay peanuts, you get monkeys."

Manual labor in many sectors is structurally underpaid. Nobody with half a brain would ever choose waiting tables as a career, even if they enjoyed it. So you're left with people with no choice or with mental-health issues (or both), who often resent having to do the job.

Whether that's by design or a collateral effect of certain societal and economic structures, is open to discussion; but this is definitely the case. Until we allow that waiter and that delivery driver a level of dignity equal to this or that white-collar job, the situation will not change.