Yes, there are prejudices built in, agreed. While not condoning those prejudices, if bigotry is hurting your earning power, maybe it's not the job for you? (Gods, I hated having to say that.) Anecdotally, I top attractive people less if they're fake. Fuck all that, "Yes sir!", "Absolutely sir!" crap. I still remember a waiter from 20-years ago that was top of class. No ass kissing, no subservient shit, spot on with doing his job, which was helping us enjoy our meal. We tipped hell out of that guy, and got a sweet recipe hand-written! (LOL, and stolen!)
If you're a top earner at a nice place, you get the best shift. That's simply doing a good job and getting rewarded. Worked for me at Lowe's, works for my wife at her job where "no one" gets weekends off, except her. And she an immigrant in a very white, solid red part of the country.
And if the restaurant's fortunes suck? Skilled servers can easily leave for a better place. OK, we can argue "easily".
As to qualifications? I've only worked back-of-house, but yeah, I'd say they are more qualified, but may not be too presentable to the public. :)
We on the same page sounds like.