And of course it's a ratchet. Nobody turns it off even as the pandemic normalizes.

I guess as long as even some small portion of the population always tips when the option is presented- they don't really have an incentive to turn it off. Like rejecting free money when your competitors aren't. I think for any reasonable attempt to stop these kinds of practices it really has to be stigmatized on the cultural level for people to feel some revulsion when asked for a tip in an inappropriate situation. If there was no option on the processor they'd probably just leave out a tip jar or continue to ask for it in an awkward and roundabout way ie hanging around waiting for you to get some cash out after the transaction is complete.