Re: The real hangup is an instinct for self-preservation.
I remember an incident from decades ago, whilst I was training to fly hang-gliders. The training involved a lot of top to bottom glides down hills, preferably those with a decent breeze blowing up the hillside. On one such occasion we were in the Dales, near Kilnsey, on one side of a big U-shaped valley. The wind speed was steadily increasing over the day, and when it came to my turn for a trip down-slope, it seemed that a critical speed had been reached.
Starting a hang glider flying is quite difficult. Merely jumping off a cliff is a recipe for sudden death; insufficient airspeed. The way you do it is to run downhill into a wind; when the airspeed gets high enough, the kite lifts you off your feet. On this run it didn't, and having run flat out down a steep slope and failed to get a glider to lift even a little bit, you tend to feel something of a fool.
This however was caused by the windspeed getting too fast. We'd gone from laminar flow down one side of the valley and up the other to turbulent vortexes spinning off the far side and actually briefly reversing the wind direction on our side of the valley; this closed down flying for the day.
The point I am trying to make is this: just a small change in conditions invisibly changes flying conditions from good to lethal. Large areas of the country will be completely off-limits to flying cars with only minimally-qualified pilots simply because these areas are potentially too dangerous. Flights over cities will similarly be forbidden; over somewhere like London the only safe crash zone is the Thames, and try getting an insurer to cover a flying vehicle that is actually programmed to ditch into a river in case of trouble!
This is what will, and does kill flying cars: insurance and difficulty. You cannot permit flights over cities, for fear of harming whatever is underneath the craft. You cannot permit flights over seas, or over rail or motorway infrastructure and so on, and you have to keep idiot pilots away from things like power lines. GPS isn't safe enough, Galileo isn't safe either, and so it goes on.
Self-driving cars are the best we're going to get.