The main problem which i have with uber (and why i dont use it - remark: i live in Germany) is that normally the licenses which you have to have to operate a taxi service work in two directions: you are allowed to do business in a give narea, but you also have to, even if certain times are not profitable for you.
And yes i appreciate that if i missed the last possible train connection at 1am in a town with 20000 people living there, still there usually will be a taxi at the station within 15 minutes, which takes me the last 20km for the same price.
In a world where we allow uber to cut away the ham (e.g. daytime trips to hotels/business) for taxi businesses, tey would clsoe down operation in such areas, and the price for this ride probably would rocket in the sky, and uber would say "oh we just enable communication between customer and provider", and the driver would say "oh, i am a business, and it did cost me 100 Euros to get here".
The point is simple: in areas whit a lower density of cars driving at night, the customer is at a systematic disadvantage (since he can not choose the provider, but the provider can easily choose the customer because 20km by car over an nearly empty road may be very fast).
So be careful what you wish for.