Philadelphia. It's not hard to hail a taxi in most places anywhere near downtown, but when you can't find one, Uber's not really a better option unless you're willing to pay over $50 for a ride.

Uber definitely has a niche where it is useful, but it's not going to displace taxis as a whole.

IMO Uber was born out of a specific fucked-up regulatory marketplace for taxis in San Francisco. Most of the taxis there are "limousine services" that are allowed to answer hails on the street. I found the situation pretty annoying, because rates are negotiated up front and are always more than what a metered taxi would cost. Many cities prohibit this because taxi drivers routinely use it to scam tourists (hence why taxi regulation exists.) Uber is a great solution for the regulatory situation in SF; but most big cities have better taxi regulation than SF.