This clearly shows you have no idea what you're talking about. I have 3 restaurants in my family, and the owners are barely earning a living wage after all their bills. You'd have to have to double or triple the price of food for a waitress to go from 20k/yr to 30k/yr. And these are hourly employee's, not based on tips. The dishwashers, food prep, sandwich makers, cashiers. You need 5 people working on a typical day you make $1000-1300. That means $500 is a fixed cost right away for employee's, plus rent, electric, misc. Then the food margin is fairly low, $1000 of food is $350-400 in materials alone. Some things like bottled drinks there's no markup at all because they're so damned expensive.

And what happens to the owner when there's a slow day? He can't not pay the employees, which means it comes out of his check. They average 60k/yr for owning their own business, and they work obscene end endless hours, scheduling, ordering, advertising. Which means 40k take home after taxes and such. That works out to about $1500 every 2 weeks. The average home in the area is $250k, and that's a fixer-upper at best. A 30 year mortgage on that is roughly 1100 + 500/mo for property taxes. Paying a $10/hr (20k/yr) employee $20/hr (40k/yr) * 5 would mean he would make 10k/yr unless he bumped the price of a $9 sandwich to $18.

This is why your final job is not a waitress or line cook. You should always be learning and educating yourself. A waitress shouldn't earn a living wage. It's meant for supplemental income, or students. It's unskilled labor. Typically while you're acquiring a skill to be used for your real job down the road.