Even if you consider it a co-pilot, unless someone is paying as much attention as if they were really driving and was right in position to take control, I don't think they could have done much to mitigate this. At best, they might have jerked the car into the next lane, but even that could cause a fatal crash of that car or surrounding cars.
My experience with the system is that it actually allows you to be more aware of things like this, because you can devote all of your attention to scanning the road far ahead, instead of switching between the distance and nearby details like where you are relative to the lines.
However, that requires using the system in a way that understands and accommodates its limitations, which not everybody does.
Are you for real? Subaru's Eyesight would have detected this, and it is much less sophisticated than Autopilot (just two visible light cameras).
In the first crash Tesla explained how it occurred (strong sunlight blocked the visible light camera, and radar failed since the truck appeared to "hover" over the road) but they haven't explain this crash. Why didn't the visible cameras cause auto-breaking?
Breaking for stationary objects is the PRIMARY purpose of auto-braking systems.
"Warning: Traffic-Aware Cruise Control can not detect all objects and may not detect a stationary vehicle or other object in the lane of travel."
"Caution: car may drive into solid objects at 70mph"
Meanwhile on the front page of HN, a system which is not calling itself autopilot manages to avoid flying a plane into the ground: https://news.ycombinator.com/item?id=12501985
Technologies like self-driving/autonomous/autopilot cars need to be very clear about what they can and cannot do. If the human has to be paying attention and able to take over before a solid object appears within the stopping distance of the car, then it should not be marketed as any of those and should limit itself to calling itself a driver assistance device.
(This whole issue is very important for people who do want fully autonomous cars, as Tesla et al messing up the PR will get them banned if they're not careful.)
Incidentally, Mercedes does advertise some of their cars as "self-driving":
https://electrek.files.wordpress.com/2016/07/mercedes-self-d...
I wonder why we don't hear these complaints about them.