My guess is that you're right: level 5 will take about as long as it takes to get to photorealistic rendering - never quite there.
The only systems safe enough to allow fully automated vehicles in the near future will have to be on dedicated lanes or roads, probably with additional safety mechanisms on the roadway itself.
https://en.wikipedia.org/wiki/Autonomous_cruise_control_syst...
I don't expect scanning lidar sensors to become common here until solid state scanning lidars reach mass production.
All of which is just to say that those voices pointing out the technical challenges are up against seriously desperate interests. This could get messy.
It's not a panacea of course.
But it would fix the firetruck problem pretty neatly, as professional vehicles will be required to stay maintained.
Also say the cars regularly ping each other for updates, then one car that was in sight and is still in sight disappears doesn't respond, then it gets flagged as a possible hazard.
Car related deaths are fairly common, I can't see any rational reason to not switch to autonomous driving as soon as they are statistically likely to save lives.
Do you really want a large (35,000 a year or so in the USA) people to die every year until autonomous cars are perfect? Not to mention nothing is ever perfect.
Doing your best and working towards safety is one thing. Putting 100% trust to autonomous thing is a different thing. If you know it's 100% safe, than it's rather easy to do. But if it's 98% safe.. It's pretty much gambling. You know it may fail and you have no chance to influence it. Sit back and hope you're not the (un)lucky one.