Ok I'll bite.
Firstly, here is the white paper:
https://www.uber.com/elevate.pdf
Your headline is misleading. Apart from transporting Bronwyn Bishop 5 miles across town, this concept is not displacing GA. In fact the Uber concept will rely on pilots (hooray!) which is probably a mistake (wait, what?). These kinds of autonomous transport in the future will be automated. Why would you waste precious weight transporting a human when that could be better spent on more batteries for longer range, or another human passenger.
Secondly, Uber are a walking dead company. They won't be around in 2020 (caveat: unless they somehow convince some more idiot investors to give them more money). Their employees are leaving in droves, they are plagued by scandals and court cases, their CEO is an asshole etc etc. Countries are clamping down on the lack of employee benefits they (don't) pay their drivers. See Italy most recently. And that is not to mention their main taxi business *burns* capital. From what I read, 1/3 of your fare has been discounted by investors. Thanks Dotcom bubble v2.0 !!
Anyway back to driverless plane: neat concept and it will happen, but won't be displacing GA for another decade at least. Battery energy density & charging times needs some breakthroughs for longer distance transportation.
What we will see in the interim is more hybrid solutions. I visited Aero-Expo this year in Europe where the theme was electric GA. Some cool developments taking place. Bigger than I realised. But still years off.
For anybody interested in what the next 10 years of technology will bring in the car space, which has relevance to aircraft, take a look at Tony Seba's video: https://youtu.be/Kxryv2XrnqM
It's very well researched and presented. Highly recommended.