My first job was driving for pizza hut. Although I wasn't working for a living while living with mommy, I had one customer who always tip big n he said the same thing. If only you know how much them drivers are making and if you tip low or no tip, why don't you drive their job to see how it was like. I was making min wages $4.25 and every delivery was a guarantee 50 cents and with no tip, that leaves me with the bare min.
It doesn't affect me as I was working to pay for gas actually. Just got a car I bought myself barely got my driver license too. Changed my perspective after that but that doesn't mean I tip well for all. I know industries where you don't have to tip n yet, they be banking so people who doesn't know that tip will make them richer than your uncle Bob's salary.