Uber serves millions of customers around the world by providing lower prices and better service, something that is not matched by taxi cabs or any similar services. Calling businesses that create so much value parasitic is a way of comparison.
Anecdotally, I have taken a trip from London to Heathrow airport 2 times, one time with a taxi cab and the other time with Uber. Uber cost two times less, and the service was on the same level or better.
Selling a dollar for 90 cents isn't revolutionary. Anyone can serve millions of customers when you operate out of the bounds of what's normally required for a business.
The main selling point of Uber/Lyft are the network effects (same app working everywhere) and the ability to judge drivers by their rating. Price IMO is not that important because people who are price-conscious drive their own vehicles. Cab companies are too fragmented to get something like such a system running.
This ironically shows how size matters a lot. Be it state investment or huge VC, more cash, more power and more centralization means better service (if the megamoney was spent well).
I agree that Uber's way of underpaying drivers is not scalable (basic mathematics) and price hikes should happen to make the numbers work out. However the service level now people expect is very much innovative.
Anecdotally, I have taken a trip from London to Heathrow airport 2 times, one time with a taxi cab and the other time with Uber. Uber cost two times less, and the service was on the same level or better.