Re: What motivation car manufacturers ?
I would guess that the motivation will be when Insurers sue Manufacturers.
Why would they do that? Insurers set the premium based on the risk profile, and if the premiums rise, unless they get the risk wrong, they make more money from those higher premiums. Whilst a little off topic, imagine the premiums (and insurer profits) of a theoretical fault free reliably self driving car that doesn't do all the risky, stupid or just incompetent stuff human drivers do, and can't be stolen. I'm guessing the car owner would pay a hundred quid a year tops.
In the UK we had at one time an epidemic of car thefts before high grade immobilisers were mandated by government. Car physical security was poor, and any criminal who wanted to take a car easily could - sometimes with nothing more sophisticated than a robust screwdriver. Car makers could have beefed up the physical security and fitted immobilisers for a trivial incremental cost, but most chose not to until forced. Car insurers muttered, but essentially did little to force the issue - because they benefited from higher premiums - not just the higher premiums across all car buyers, but also because a theft claim caused the driver to lose their no claim bonus and the insurance industry benefited by classing those unlucky theft victims as "higher risk" in subsequent years.
The people who weren't happy were the owners who lost cars and paid higher premiums, and the police fighting a losing battle to stop theft. It's looking like car software will be the same.