So what if I was raised to tip 10%? (edit: I've noticed my dad usually tips about 10%, even if the service was fine. Some might see that as "bad" tipping, but maybe 10% was normal for most of his life? Is he supposed to track and keep up with inflation now?) Some people say 15% is standard. Will that prevent my food from being spit on? Some people have said 20% is standard. Some states have stronger minimum wage laws, do I tip less there? Some states have higher cost of living, do I tip more there? I know I tip restaurants, sure. Oh yeah, and pizza delivery drivers. But wait, package delivery drivers don't get tips? And they do far more heavy lifting than a pizza delivery person. But I get it, pizza delivery drivers only get minimum wage, and it's an extra optional service, that's why you should tip. Oh, look, there's a delivery fee that gets charged when I order delivery, obviously that means that the cost of delivery is covered by that, right?
Taxi drivers? Do I have to tip on Uber? They drive me around too. So does the local bus service, do I tip the bus driver as well? The person who takes my luggage at the hotel is supposed to be tip. I think. But I can take my own luggage, do I have to run the person down when they rush to grab my luggage, because I actually don't want to pay for the "service"?
Arguing for payment based on a vague thing like "tradition" may be a "functional" system, but I have no idea how one could argue that it should be the preferred or optimal system. Healthcare through an employer is "tradition" in the US, but it's hardly the best way to provide health care services to a nation, according to pretty much all evidence.