And you think that a human alternative to conveyor belt is worth more than the current minimal wage?
You got the whole thing wrong, and you managed to insult every waiter and waitress in the process:
A waiter does so much more than that. They generally take care of you - they help you to choose your places to your liking, undress, seat, they recommend food based on their expertise and clever judging of their client, and so on - they generally take care of you, and that can and is (and should) way more complex than being a human conveyor belt.
The actual argument is whether this job is a job done to the customer or to the restaurant (because it can be thought of as a whole package service or their image).
Americans think that the waiter will help a client more if the client is the person who pays them - literally, with actual cash changing hands.
Other people don't. I'm from such country and sometimes it leads to horrendous results, however most of the time it's OK - yeah, "OK", never great, so I definitely can see the point the Americans have.
Overall, IMO there are places where human staff is appropriate (fine dining places, brewery, upclass cafe...) - tipping is appropriate here. Of course there are places where the point is to obtain a plate and eat everything as soon as possible so you can be gone - but IMO people shouldn't serve the plates at these places.