As a data point to the contrary, in Chicago we stopped calling taxi dispatchers to our apartment because they would arrive up to 30 minutes late. Even if we scheduled ahead of time, it didn't seem to matter; as if the dispatchers were holding our request until the last minute and then dispatching into the general queue (so why call ahead?)

With the Uber app, whenever we call a car (even a taxi) we get an ETA based on GPS coordinates of the driver, which is both accurate and updates live. There's a level of accountability that was never available with the existing taxi dispatch.