There's certainly a market for app/phone jailable cabs because there isn't one within street hail range at all times, but regular cabs have been phone hailable forever (it's the only way to get one outside of a few major urban cores) and are increasingly app hailable. Aside from regulatory supply restrictions (flouting which may not be sustainable) there's no real basis for a market for alt-taxis as anything but interchangeable competitors supplying the same substitutable commodity as regular taxis.

For me, this wasn't particularly true, especially in San Francisco. The dispatch was unreliable and slow.

Other areas, sure!

Now that the idea of phone-trackable dispatch has become commonplace, regular taxi companies are starting to do this too.

With Uber you also get know the fare upfront, the time of arrival, no need to tell them your address, there is a driver reputation filter, passenger insurance and it's safer than normal cabs in many countries.

Not the same thing as a phone call.