If the software improves beyond a certain point, insurers would be willing to take on the risk of this aftermarket approach, making it viable to run a business installing this on cars. Regular consumers wouldn't have to be hacker types to want this or know anything about how it's installed.

For that matter, at a certain point your car insurance might give you a big discount to have one installed and subsidize the installation and hardware costs. There's a profit motive for the first company that does so, being able to offer much cheaper rates while still paying out far less for at-fault collisions.