A self-balancing quadcopter is probably not any harder to fly than a car is to drive, but self-flying would be safer. I think the bigger problems would be:

1. Landing/takeoff space near city centers
2. Noise
3. Battery life
4. Adverse weather (icing, wind)
5. Bird strike

I hope I’m wrong, but flying to work will likely remain the province of the rich for the foreseeable future.