Service industry people in the US are not well paid and you're tips make them their living. I don't like the system either but that's the way it is.
Also as I said a lot of the service industry are well paid, bar tenders definitely do yet get tipped heavily for example.
I still tip over there as their ridiculous system would nearly mean you are treated as not paying if you don’t. But outside the US I won’t tip, I’m very strongly against it and have often ended up in arguments out with friends as I will simply not add extra money to the pot for a tip and that sort of thing. It’s an idiotic practice that if everyone stopped doing it the expectation would stop.