Most people seem not to tip baristas at all. I make my own coffee 99% of the time, so on the few days per year when I buy it, I tip around 20% because it's a luxury, and if everyone who could easily afford the extra few dollars did so, baristas might actually have fair income. Same for eating at restaurants, etc.

I acknowledge that it's a workaround for a larger problem, but I have low confidence that the US will actually address that problem within my lifetime.