That line of thinking is erroneous in my opinion. Autonomous technology only needs to kill a few less people than the existing manual technology to be worth debating, and it's a no brainer if it kills orders of magnitude less people.
About 1 in a million people die annually by car accident per VMT (vehicle-miles travelled) [0] and the number's declining. So if Tesla sells a thousand cars, each travelling a thousand miles that kill 2 people in the first year, they're already above the mark. If there was a person between the truck and Tesla they'd be way above the mark. Even more so when you consider "Summon Mode" isn't full self-driving and is probably only being used less than .1% the time the car is turned on.
More problems are caused by taking things too fast than taking it too slow. Full self driving cars are probably farther off than you guys seem to think.
There are somewhere around 100,000 Tesla cars on the road (as of end of 2015). If each is driven say 10,000 miles that is a total of 1000 Million miles driven. At the current US average of over 1 fatality per 100 Millon miles driven that would make 10 fatalities per year expected from Tesla drivers.
Not all Tesla cars are going to be driven in self-driving mode at first, so we can expect the numbers to look much worse early on. If only 20 percent of Tesla drivers let the cars self-drive (and of course only the newer Teslas will be capable of self driving because of sensors, etc.) we are down to 2 deaths expected by human drivers in that 20 percent.
I used to think that these kinds of numbers would act as a barrier to the development of self-driving cars, but each time one car has an accident all of the cars will learn how to avoid it the next time. Every human driver has to learn what to do around icy roads, what to do when cut off by a car in a neighboring lane, what to do when approaching a neighborhood where kids and dogs are playing ball in the front yards, but a self-driving car only has to learn once and all the other self-driving cars will know what to do too.
When I was growing up, there were around 6 or 7 times as many people killed per vehicle-miles traveled. I hope that self-driving cars won't be as dangerous as the cars of the 50's and 60's when they first hit the road. In the longer run as thousands and eventually millions of self-driving cars begin driving I expect them to improve rapidly though their shared experiences.
That is dependent on them actually being software-fixable problems.
In this case, the sensors do not actually monitor the complete space taken up by the vehicle, so this kind of accident would be impossible to prevent by modifying software.
