We have direct evidence to the contrary. Uber disallows tipping and pays somewhat substantially less than Lyft.

It's great that you want people to be paid sanely for the job they do, but the fact of the matter is people largely aren't in this industry. Uber doesn't allow tipping, and doesn't pay particularly well. After factoring in depreciation of their vehicle most drivers are going to be bringing in something like $10/hr.

We live in a culture where businesses won't pay their employees sanely. Until that is fixed I want the ability to show my gratitude for a job well done with a tip. "Blah blah use cash!" Sure I can do that, but it's inconvenient for a number of reasons and the reality is that most people won't do it.

Absolutely agree with this point. I hear the same argument for restaurant waiters and I hate this tipping system that even has suggested tipping tiers. It only tells me that owners of these establishments are not paying their employees correctly. I know of places which don't even disburse the tips back to their employees (when tip is part of receipt)!

At least in CA, waiters still get full minimum wage.

Recently some fancy restaurants in NZ have started asking if I want to tip (tipping has never been common practice in NZ). I always refuse and state this exact reason. As soon as customers are expected to tip, workers get exploited.

I'm not tipping you for your own (long-term) good.

NZ has a similar minimum wage to Australia, right?

I think some of it is (stupidly) driven by new credit card / eftpos machines that have the tipping option built in.