Traditional taxi drivers need to be less grubby -- Uber was able to take advantage of that. How important a factor that is would depend on the country or city. But in some countries, it may be a way of filtering for drivers that speak English. For example, for Tokyo, Uber lists a flat rate of 40,000 yen, roughly 400 USD (!), for a ride from Narita Airport to any of the 23 wards of Tokyo. Pretty steep, given that a very nice bus, hotel shuttle, or express train is less than a tenth of that cost. Of course, the "last mile" is a consideration. For taxis, though, there are already established taxi services; http://www.narita-airport.jp/en/access/bus/#taxi shows that fixed fares range from 16,000 - 26,500 yen.