Calling for a cab was extremely unreliable here. You could easily wait for an hour (because any driver coming to pick you up could, without ill effect for him/herself, stop to pick somebody up on the street). Some cabs took credit cards, some didn't. Some claimed to take credit cards but then "the machine was broken" so you had to pay cash.
Uber improved on every single aspect of the customer experience. And they did it while offering lower prices for the consumer.
However: to me, they haven't proven it's a viable, long term model. I highly doubt that they are paying their drivers enough to cover the cost of wear and tear on the cars (many/most of the drivers I see with Uber and Lyft are doing it full time, so they are crazy if they aren't factoring in the cost of the car and maintenance as part of their cost). And AFAIK neither company has proven they can make money.
So: this industry was due for a shakeup.
But it needs to be done by a company without rampant management problems, and it still needs to prove that there is a viable, long term business model that works for the company, the drivers and the consumers.
[edit: and, yes -- long term, there won't be drivers in these cars. But Uber has to find a way to survive until then, and I don't believe they can burn cash that long]