I don't know man, it seems clearer and clearer that we just come from different places. Nothing against you or wherever you come from.
I was raised to tip service employees in general, if you can, if they have to bring you something... and to tip more if they keep my glass of water full (I tend to drink a lot of water), so it just seems natural to me to tip.
I don't think it's just (though it is a fact) that wages are reduced because "wages don't need to be so high, because of tips." I have worked service industry jobs where I was not tipped, and I'm so glad I don't have to do that kind of work anymore. I would not be any more enthusiastic about those jobs if I was tipped. It wasn't satisfying work for me, and I have a hard time believing it would be for anyone else, but I try not to wear that on my sleeve.
Not everyone gets the chances I got! Not everyone would like my job as much as I do, either. I am very sympathetic to the idea that you shouldn't make every interaction into a business transaction, but in this case you have to recognize that it is what it is.
You are getting into someone's car and they are taking your pittance, minus their service broker's fee, to bring you where you need to go. That is a business transaction, and it's in the class of transactions that I would expect to involve a tip. That's just how I was raised. I understand if you do this five or six times a week, you may not want to interact with these people any more than you have to so you can get where you need to be and get on with your life, but I do it less frequently and I am just as happy not to ride in silence!
If you do this job in your off hours, and you work in maintenance at a corndog factory for your regular job, I actually want to hear about that. I will strike up a conversation if the driver seems willing.
I don't come from a place where people routinely complain about not getting tipped though. (If you hear someone complain about a tip, I tend to assume the service was also poor, and they earned exactly the tip they got! Some people are assholes, but not most people.)
I think of Uber and Lyft as an exceedingly cheap way to get around. In bigger cities I've visited, it seems like it's more of "a somewhat competitively priced way to get around that's marginally more convenient than public transit options, sometimes. And often cheaper than parking if you were thinking about driving yourself." Where I live and where I come from, parking is almost always free, and public transit is almost never an option. (Buses are the only public option, unless you're going out of town -- then there's Amtrak -- and the buses are significantly less convenient than they once were, since schedules and routes have been drastically reduced in recent years. There is no subway. Cabs-for-hire tend to be outrageously priced.)
Where I lived before Northern Indiana (now), was in Western New York, we didn't even have Uber at all and you couldn't really get a cab ride for under $30. Get on the bus. I don't know if it was an economic decision for Uber or a regulatory issue, but I don't know how anyone honestly can live there without a car. I did it for a few years of college and a year after that which I spent mostly too broke to afford a car or insurance payments, and it wasn't easy. (On the other hand I will admit I was in much better shape then!)