1) Uber depends heavily on their app for navigation and billing. Street fares short-circuit that and make it difficult for their app to get involved. Also, with no guarantee of the app being involved, there's nothing to stop a driver from demanding payment in cash and pocketing the money; any driver who does that is outright competing with Uber.
2) Only a very few places have hailable cabs to begin with. It requires that both the typical starting point and the typical drop-off point be in a dense urban core, and even then it'll still only work if hailing cabs is part of the local culture. It'll work in New York, but nobody's going to hail an Uber in Dallas because nobody hails cabs here. Dallas is mostly suburb: Downtown-to-Downtown cab rides are rare to nonexistent here, and even when they happen, hailing cabs just isn't part of the local culture.
3) Hailable taxicabs are clearly marked as taxis. Ubers are just people's personal cars. Nobody is going to stand on the street and hail random cars that drive by, and if they do, that's called hitchhiking.
1) Uber depends heavily on their app for navigation and billing. Street fares short-circuit that and make it difficult for their app to get involved. Also, with no guarantee of the app being involved, there's nothing to stop a driver from demanding payment in cash and pocketing the money; any driver who does that is outright competing with Uber.
2) Only a very few places have hailable cabs to begin with. It requires that both the typical starting point and the typical drop-off point be in a dense urban core, and even then it'll still only work if hailing cabs is part of the local culture. It'll work in New York, but nobody's going to hail an Uber in Dallas because nobody hails cabs here. Dallas is mostly suburb: Downtown-to-Downtown cab rides are rare to nonexistent here, and even when they happen, hailing cabs just isn't part of the local culture.
3) Hailable taxicabs are clearly marked as taxis. Ubers are just people's personal cars. Nobody is going to stand on the street and hail random cars that drive by, and if they do, that's called hitchhiking.