Transportation technology stagnated since the '70. That's correct.
Other technologies/sciences, on the other hand - computing, biology, etc - are advancing nicely.
About the legalisms surrounding driver-assist technology:
It depends on its safety.
If it's unsafe, it will not drive cars - not alone, anyway.
If it's safe enough (as in, probabilistically safer than human drivers), it will drive cars alone.
Eventual accidents will be the responsibility (vis a vis criminal law):
- of the proprietor of the car/person who has the obligation to maintain said car: if they're due to malfunctions of the technology.
-person in charge of quality control: if they're due to the lacking quality of the technology as it exists the factory.
This is not the first time such issues have appeared. They don't require a revolution in law to be solved.