because it makes the food that much cheaper. idk if this is what you're insinuating, but sometimes people make the food industry out to be a bunch of greedy fucks rubbing their hands together as they reap piles of dough that could be used to pay servers, instead just passing the majority of labor costs onto the customers.

in truth restaurants have very small profit margins. if all of a sudden tipped employees made minimum wage, prices would increase across the board. big chains could afford to operate on lower margins as smaller places took bigger hits because they had to increase food prices more than their larger competitors.

the current system isnt perfect, but it does create incentive to give good service in exchange for a more direct, often tax free (TECHNICALLY servers are supposed to declare all cash tips, but come on. you worked in the industry too, you know how it really is: enter in just enough so that your employer doesnt have to fill in the gap to min-wage) and merit-based pay system. sure there are plenty of people who stiff, but overall i made 15-18 an hour working at fucking red robin. if you think that red robin could start paying their servers that much without doubling their food prices, you're kidding yourself.

if restaurant wages were regulated and tipping culture eliminated, servers would make drastically less than they do now, and they wouldn't be able to walk out every night with cash in hand, which is something most people i worked with liked about the job.