Um, OK.
Uber is not so much a tourist service. You see it most big cities as a way to take people to-from restaurants/clubs/bars with up-front pricing via a secure dispatch, compared to taxi services - which are all pretty much scams anyway.
Orlando is not just tourists. There are many thriving cultural areas - downtown, Thornton Park, Winter Park, College Park, etc. If you think Orlando is just theme parks, well ...
I don't think it's just theme parks, but I DO think -- hell, I KNOW -- that it's central Florida, and just about everyone who lives there who CAN drive, does drive. The percentage of non-drivers who live in Orange County AND have enough income to regularly afford the fees of a service like Uber over the distances normally involved is pretty small. Uber *is* a great service, but it costs more per mile than a regular cab does, so it needs a certain level of affluence in the market.
As with any private livery model, you can only make a profit if you have a critical mass of people moving between a limited number of points that are relatively closely co-located but present some disadvantage in using a personal vehicle. In Orlando, most of those points involve hotel districts and theme parks, and the critical mass is created by tourists who do not have personal vehicles at their disposal. (In NYC, they are created by residents and tourists moving around Manhattan and to and from the airports: any driver who says that he makes his target income doing other runs between boroughs is pulling your leg. With the possible exception of the Bronx, where it hovers at around 50%, the rate of car ownership in the outer boroughs mean that far more households there own a car than do not. Only in Manhattan are the car-less a solid majority of the residents.)
I've been dealing with how to drive home after drinking for over 30 years now. Like everyone else I know in flyover country who doesn't live really close to where they socialize, I just pace myself and don't get behind the wheel until I've had time to sober up, or I make sure that there is a designated driver in my party.
PS: Obviously I'm not the OP, but if I had to guess, I'd say the objection to conventional taxicabs is primarily that they do not quote a flat fare up-front. Lord knows, if you get stuck in the congestion around DTD on a weekend, that meter is going to cost you.