IMHO, one of the employers responsibility is to pay their staff. I don't think that's really arbitrary, it's commonly accepted across the world.
If you're in the service industry, it's your job to be nice. That's what their employer (hopefully) pays them for.
If I have a good or bad experience, I exercise my discretion by choosing whether to go there again. If the employer notices a trend downwards in customers, it's their responsibility to assess what that is - hopefully their in touch enough with their business to identify if it's because of their employees service and 'apply pressure' if need be.
I guess ultimately it comes down to culture. I (and the large majority of the non-US world) isn't accustom to paying 10%+ extra for bad or rude service and it would be very hard for us to understand why that happens.
Nope. I pay so someone else cooks my food and I have a nice selection. In fact anytime I've eaten at a restaurant in the US I hated the service. They just won't leave you alone because they want to be your friend so you will tip them. I don't need you to check how I'm doing every 10 minutes.
Tipping is about connecting the buyers and sellers of services directly. How does sending the money through a manager/owner result in better or more cost effective services?