I think you're way too pessimistic here:
(1) A whole industry of rent seekers (medallion owners) was mostly run off
(2) The taxi experience in cities other than NYC, Chicago, and SF got a million times better. Before Uber in a city like Nashville you call for a taxi and maybe one shows up at some point. Since Uber you can reliably get a ride whenever you want. And that's not even talking about discrimination.
(3) Uber caused a dramatic decline in drunk driving. Likely because of (2)
(4) It allowed people to make some money with a flexibility that traditional jobs don't offer
For me, Uber/Lyft has definitely had the biggest positive impact on my life out of any tech company in the last decade. The only close competitor would be Android/iPhone. I don't know if Uber is worth the ~60 billion that they were last valued at, but they definitely fill a legitimate role.