Personally I think if staff do not receive a living wage, then every penny of profit goes to the business owners. I know a lot of Americans are business owners, but much fewer people in the UK are, so we see those people as skimming our money.
I work in the gig economy - I have had about 4 tips in over 20 years, but my fee is fair, so I really was never expecting it. Just to say, it was mostly the poorest people I served who tipped me!
Anyway, we will pay the service charge, and only tip if someone does something extra for us.