I disagree with this in part -- I will agree with you that most of these people deserve to be paid more regardless, but I disagree in the sense that they all be paid uniformly. Better service should get a better tip. If that's priced in, I have no choice in the matter, I am paying the same price for subpar or lackluster service. This would make me change services as a whole rather than just chalk it up to I had a bad driver. Allowing me to tip based on the level of service I receive is a form of recourse for the customer in the event of a terrible experience. It's also an incentive to the driver to perform better.
Paywalls are absolutely fair game to me. I have been a long time subscriber of giantbomb.com and wish more makers go that route.