I could imagine a not too distant future in which tipping evolves into a quasi-fixed-rate quasi-tax, with only exceptional or atrocious service warranting a deviation from a cemented social norm.
Another similar example (probably outdated): airport skycaps.
An example of a tipping system in America that doesn't work that way (yet) is hotel housekeeping; a surprising number of people don't even know that there's a tipping custom there at all.
The "quasi tax" thing sounds alarming, but it doesn't bother me at all; it's just another way of expressing costs and prices. Things will cost what they cost one way or the other. If tipping becomes so common that everything has 5-15% tacked onto it (I doubt it'll happen, but we'll stipulate), base prices will fall. Businesses can't simply banish demand curves! There is ultimately a market clearing price.
Ah, yes, that is in fact almost exactly my mental model for how to tip in restaurants or cafes (albeit with a conversion factor to the rate I was socialized with).
What always blindsides me is tipping in a place I (or even some locals, apparently?) don't expect it. And generally speaking, I much prefer taking social cues from local friends or other patrons than from a device.
