100% Agree that people should just be paid more. But it's not that simple ...
Raising wages has an inflationary effect on the prices in the restaurants/bars. And the people who suffer from inflation are the minimum wage earners who spend proportionally more of their disposable income on essentials like groceries.
I worked as a waiter/bartender for 3 years in college and the wages were terrible! But I always made an effort and customers gave me tips. Saved those tips to buy my first iMac which I used to learn higher-paying skills.
Having been a service industry worker and now in a different income bracket I always tip for good service. Without tips many people in the service sector could not get by.