[MrDom]

We have computer-controlled braking and throttles now

Couldn't the same case be made for doing your own mechanic work, though? We have braking, which is hydraulic and throttles which operate by wire. There's nothing preventing you from replacing the tried and true hydraulic brakes with something that runs on bluetooth. That would be just as dangerous as messing with the software of modern car brakes. More so, since one would hope modern car software has some failsafes built in[0].

[0]: they probably don't, but I know Sevcon does. Sevcon is a company that makes electric vehicle controllers for EV vehicles. They're popular with the DIY e-motorcycle crowd. Messing with the settings directly affects the power delivered to the motor.

[stolio]

Pulling out your old throttle system is hard. It's self-protecting, the difficulty keeps the uninitiated from doing anything too stupid.

Copy/pasting code from the internet is easy, so it has to be made artificially difficult. We live in a world where people put their iPhones in microwaves because they heard it would charge the battery. We have to keep these people very far away from the internal workings of their cars.

[MrDom]

Have you ever tried to program a controller? It's hard too. You need special hardware, special software and know how to connect them all up. It's not just copying and pasting code from the internet. It's sufficiently discouraging for those who think microwaves are wireless battery chargers. :)

If you're curious, you should poke around http://endless-sphere.com/forums/.