OK, so now we are in agreement. At McDonalds, you do not get waited on by a person who is working for tips. You get served by a person being paid a straight salary.
You suggested that tips were what made sure you got good service. How do you expect to get correct service from McDonalds, or any restaurant where you order at a counter or a drive-thru? Or do you just assume they will all have lousy service?
My argument is that you CAN get good service, because there are different motivations. Most people who are employed provide good service for a salary or hourly wage because they feel they are compensated appropriately, and have a good work ethic.
Now, back to waiters and waitresses. Their service is not cooking your food, or bagging your food, or ringing up your order in a drive thru, like the jobs you mentioned.
Waiters and waitresses wait on you, at the table. If they do a better than average job, they will earn better than average tips. And that, for the umpteenth time, is their incentive to provide good service.
If you don’t like the system, then avoid restaurants with waiters and waitresses.