The issue is that you're vehemently defending this practice. As far as I can tell the only reason for this is simply because of momentum. None of the arguments you are making really make much sense. There's strong evidence to the contrary in fact. Not only is the practice particularly unique to America (and Canada), but the practice and laws defending it just enable wage theft (employers not paying minimum wages by claiming tip credits that don't exist). The practice was developed during feudalism and was a form of oppression. The current practice also divides the working class and prevents them from working together in a larger coalition advocating for a larger minimum wage. No one here is really against the concept of tipping, but people are upset about its expansion and that the practice is essentially required. You have said that the money is optional, but we all know that this isn't exactly true. Technically/legally yes, but in practice this doesn't work out. People aren't tipping for service, they are tipping to avoid bad service (as many have said here) and to avoid social stigma from their peers. This is not the system you have laid out in your many comments, this is just a convoluted form of class oppression and wage theft. Sometimes we need to reevaluate things we've been doing just for the sake of doing. Momentum is not a reason to continue a harmful practice.

Is it on a good track to continue existing, though?

TFA is specifically describing how the kind and number of situations in which a tip is expected/asked for (if only by a payment terminal interface) is rapidly expanding – and if every service is tipped, no service is tipped.