'Stiffing the server' does not correct the problem, and may contribute to the continued employment of a server who does not need to continue in the service industry as it will generate sympathy for a person who may not deserve that sympathy.
Oh, I don't doubt that. But the person stiffing the server in any particular instance simply may not care that much. It tends not to be a problem-solving behaviour so much as an emotional lashing-out.
At any rate, as far as problem-solving and efficient feedback goes:
The ownership of the restaurant is very, very eager to hear customer feedback and would gladly do what is necessary, including refunding the cost of the meal, providing discounts for the next meal, etc. to mitigate the effects of bad service.
A refund is all very well, discounts for the next meal maybe useful or not depending on whether I plan to come back, but nothing more than that is likely to happen and at any rate demanding that the customer go off and deal with head office misses the basic point that the person encountering bad service is most motivated to provide feedback to the server. And there was supposed to be a mechanism already in place for commenting on bad service and good, and that mechanism was supposed to be the tip, and the reason it was originally structured that way was that it gave an option to provide this sort of feedback without having to go over the server's head to his manager or the restaurant's ownership.
In the present American system this feedback function is broken, of course, but that's not a feature of the system. It's a very serious defect.