Unless you know something about the upcoming price of cars that you'd like to share ;).
In 5 years how many cars will be equipped with the basal level of sensors that make these sorts of hacks possible? My guess is more people will have compatible cars in their house than qudrotors....
Cost and chance of failure is poorly (or not at all) evaluated by the kinds of dangerous beginners likely to crash their car-pilot into a bridge.
The people who are out there with quadcopters are the same people who would be doing these hacks at home on cars; some hobbyist/tinkerer subset of nerd.
I don't share your low opinion of their threat evaluation functions either.
If you follow that premise, it becomes less safe to drive manually.
So, under this premise, the modus operandi is to be automatic pilot instead of manual where perhaps manual driving is even illegal because it is less predictable.
The question wouldn't be, if this change happens; its when. Where's the turning point? One could argue its up to our politicians to decide. I'd be interested in data from other trends such as smoking. When was the turning point there, and what was the "market penetration" of smokers vs non-smokers or proponents and opposers?