Since ours in the US is generally a percentage of the bill, people in expensive restaurants can make more. Do they work harder? Do they have fewer tables so less checks are tipping? 20% tips on 5 hundred dollar tables is $100 every 60-90 minutes, but shifts are usually only a few hours. So maybe $3-400 for a 4-5 hour dinner shift? In a diner you’d are probably half that per table but for more tables and faster turnover. What’s a good wage?
I think the counter argument is, should someone who spent decades training to do a job be paid the same as someone who just walked in off the street?
When you’re talking about justifying paying someone less, the people who think that way would be happy to see neurosurgeons paid $2 + tips, but they can’t make it stick because someone else would be happy to pay them whatever they ask for if it means they get to live longer.
However, I’m not in favor of the term, “unskilled labor”. I don’t think it really applies to any job. I prefer “entry level” when you’re talking about a job someone can do without any prior training.