As someone who has ridden my entire life, I agree with your comments about Reeve's riding ability. I saw the footage of the accident, and he made a common novice mistake called 'jumping up the horse's neck'. Instead of letting the horse's momentum lift him out of the saddle over the jump he anticipated the jump and got in position before the horse was ready. He was a big, heavy guy and the horse decided it couldn't get over the jump with its rider's weight off balance and slammed on the brakes.
Reeve was incredibly unlucky to have this accident result in a broken neck, however. I've had the same thing happen to me. I've fallen off in every way imaginable and have always walked away. If you ride horses you are going to part company every so often - that's just part of the sport.
I've never seen the footage but I have seen people jumping ahead and not letting the horse's momentum lift them out of the saddle. A classic way of getting dumped, for sure.
Since I switched to a combined training barn, I ride more in a "safety seat" and don't get hung out to dry when a horse refuses. On the other hand, I was out hunting last season and my 100 percent reliable bombproof mare actually FELL DOWN just cantering up a hill. We'd been out a couple of hours and had a couple of fast runs, so she was a little tired, and I think she hit a wet patch and her feet just shot out from under her. I rolled off her shoulder and was on my feet before she was. We both were fine, but the expression on her face was a study. She was highly embarassed.
I've been riding for 45 years - since I was 5 or 6 years old. I've accumulated a few injuries along the way - broken nose, torn ACL, bruised ribs . . . the only serious one in 45 years was a badly broken finger that basically had to be reassembled on the surgery table. It doesn't even ache when the weather changes, though, thanks to glucosamine/chondroitin tablets. And that didn't happen in the hunting field or on the cross-country course - I was working a big doofus of a Quarter Horse over a small grid and he tripped over his own feet and fell down.
I agree with you that Reeve was just incredibly unfortunate. I've shot off over the horse's head many, many times . . . about 20 years ago, riding somebody else's horse that was very heavy on the forehand, I came off four times in a one-hour lesson! (I didn't ride that horse any more.) It comes with the territory - but usually the consequences aren't that severe. On the other hand, I know somebody who sustained a severe head injury falling in the bathtub . . . there are no guarantees.
BTW, if you saw the film, is there any truth to the rumor I heard that he had his reins wrapped around his hands and so could not catch himself?