I like to approach this question by thinking of incentives.
I would add two more elements to your three listed reasons: (1) mature alternatives (2) risk aversion which causes general adoption of a new technologies to take a long time.
While the promise of self-driving cars could bring lots of benefits, the current alternatives are so advanced and refined that there is not a huge urgency to switch to the new alternatives yet.
People and governments resist new technologies and need lots of assurances before the new (driverless cars, etc.) is accepted.
Consider an imperfect example/analogy: Covid vaccines happened way faster than anything like it in history because of the extreme incentives involved—the world had ground to a halt and many thousands of people were dying daily.
I like to approach this question by thinking of incentives.
I would add two more elements to your three listed reasons: (1) mature alternatives (2) risk aversion which causes general adoption of a new technologies to take a long time.
While the promise of self-driving cars could bring lots of benefits, the current alternatives are so advanced and refined that there is not a huge urgency to switch to the new alternatives yet.
People and governments resist new technologies and need lots of assurances before the new (driverless cars, etc.) is accepted.
Consider an imperfect example/analogy: Covid vaccines happened way faster than anything like it in history because of the extreme incentives involved—the world had ground to a halt and many thousands of people were dying daily.