Tyler Cowen:

Let’s say you are optimistic about the long-run prospects for Uber to transform society, as I am.
 Counterintuitively, that could mean the perceived quality of an Uber ride goes down.
 The better Uber gets, the more people can do without cars and the more taxis will go out of business. In contrast, we are currently living in a world where there is excess capacity of automobiles, especially for short-term rental. The stocks of taxis, rental cars, and personal automobiles mostly have been determined by past considerations which did not take the existence of Uber into account. Those stocks will decline over time as idle vehicles are used more efficiently. There will be fewer circulating vehicles and perhaps the price of a short-term ride will be higher, once the excess capacity disappears.
 Waiting time might be higher too.