Absolutely don't understand this discussion at all, as an old guy. I learned to leave a tip for service from my father, at hotels and restaurants, and for cabbies, bellhops, Red Caps, Pullman porters, wait staff, bartenders, and just about anyone else who went "above and beyond" in helping our journey through life be more pleasant. We weren't a wealthy family, by any means, but we valued the people in service industries who cared for our travel experience. That started damned near sixty years ago, so this isn't a "new" concept by any means. Someone's salary didn't figure into the decision; it was simply a genteel way to say "Thank You."
If there is a problem, I pass it on to a manager. To this day, if I receive good care from someone in the service industry, I find out their name and pass on a compliment to their manager, in addition to thanking them personally and with an appropriate tip. It's a nice thing to do, which costs almost nothing at all over the long haul.
The few minutes of time and relatively small amount of money spent in such ways over forty-five years of traveling hasn't changed my life for the worse in any measurable way.
Don't care much how anyone else lives their life, but never understood personally the need to be an ass for the sake of a dirty piece of paper in my wallet or the change in my pocket.
Of course, I still wear a tie when I fly in coach, and I drink Gin Martinis, too. Ain't many of us left from that bygone era, and your mileage may vary by year of birth ...