Is safety on the road possible?

I've worked at a bike shop for less than a month, and already I've had a customer bring a bike in for repairs from a auto/bike accident.

Basic facts are as follows:
John(we'll call him) was biking alone during the day on a county highway in NW Iowa. Time was around 6 pm, John was northbound. Local traffic is light, about 500 vehicles per day. Conditions were clear, visibility unlimited by weather or terrain. He was in kit with helmet, riding one to two feet left of the white fog line. John had reflectors, no lights. A pickup truck approached from behind and struck John with the passenger side of the vehicle. The truck was traveling at highway speed, roughly 55-60 mph. Driver reports never seeing John. Driver is less than 30 yrs old. The driver initially thought he had struck a deer until he saw John behind him, lying down on the highway. John broke the headlight and side mirror of the truck, after which he fell, coming to a stop roughly in the center of the highway. John suffered multiple torn tendons in his left shoulder along with severe road rash and bruising. He spent a week in the hospital with a blood clot in his left lung, and has had at least one surgery to repair damage to his shoulder. Driver was cited for failure to yield three feet when passing cyclist. Fine approximately $450. John's medical bills are substantial but the driver's insurance will cover majority.

The crash was in July, John was able to take the sling off his arm only recently. He has been cleared to ride a trainer, and so brought his bike in for repairs. Bike needs tune-up and wheels slightly trued, John took the brunt of the impact.

John said that he has been told by multiple people to quit riding. He plans to add a flashing tail light, but no other changes.

These are the facts as I best I can recall.
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This is the first conversation that I've had with a cyclist after a major accident. John is fortunate to have survived the impact, in part because he glanced off the side of the truck instead of going under it.  Given the conditions during the accident it's possible that some form of distracted driving was involved.
John seems to be without bitterness regarding the accident.

What disturbs me the most is that there is nothing John could have done differently to prevent being hit. He adhered to every rule, written and implied, regarding how a cyclist should use the road. He could have made himself more visible by taking the entire lane, but he may also have been killed taking the full force of the impact. A flashing light may have helped, but its effectiveness would be limited by the bright light of a July day. It is impossible to really know.

So: Is safety on the road possible?