As with most such events, it's usually a succession of errors or accidents that lead to tragedy. When there's it's a death or serious injury, the story is almost universally about more than one failure along the way.
We've all encountered challenges, but the idea is to stop the dominoes from falling. This guy knocked over several, but the simple act of buying and carrying the PLB was the difference for him - it was one choice among many. Gear, training, attitude, etc. are all choices that can save the last domino from going over. Personally, I'll carry as many of those "saves" as I can get.