I see what you’re saying. As I think about all the interactions I have with people who work with the public, the vast majority of them are perfunctory. Bank teller: polite, but matter of fact. Guy at the tire store: same. Tech support guy for my cell provider: foreign; unable to understand.
Come to think of it, the people who are most personable with me are the guys I see pretty consistently at the cafe I frequent. They make more than minimum wage, and I usually forget to throw tips in the jar, but I know they aren’t working for their tips. They’re personal because we have regular interactions, I’m a regular customer, not because I’m throwing bones to hungry dogs. There’s comfort in familiarity; it relaxes both customers and service workers.
I work in retail, I am friendly, polite, and attentive to our customers. I’m paid to do that. On occasion, an interaction will become a little friendlier, more personable, and presumably more uplifting for that customer. Not because I’m being tipped, but because it’s genuine.
You’re probably right that some interactions will become more perfunctory, but I think that’s to be expected as it is in every other service job. The difference is when you find workers, in whatever service job, that truly enjoy interacting with people and that’s why they are in service to begin with. The absence of the arbitrary reward system that is tipping is not going turn those folks into automatons, I can assure you. But maybe it will weed out folks that aren’t suited for that type of work.