Look, I come from an era of no protection other than your pads, box and, as Brian Close once said, "You've a bat, bl--dy well use it."
For those vague of history, just google the Bodyline series of 1932-33 and you realise that the use of intimidatory bowling was a bit more than now!
The point on the hats and protection (look at the thigh pads, the shoulder pads, elbow guards etc etc) and the point that letting the ball hit the body is so common now-adays, the bat kept well out of the way for if there's a click there can be a catch and it's walkies time. So technique does help....
There's also the role of the umpire, persistent bouncer bowling is not permitted and if it gets to be more than two in an over, the umpires will step in, warn and then, if necessary, ban the player from bowling for the rest of the innings.
This was an unfortunate accident, if it had been a 1/4 of an inch either side, he probably would have been okay as it was his vertebral artery that was caught square on and it split like a water-leak, flooding the brain. It will force some re-thinking of helmet design and that's fine, perhaps a lower lip over the neck but ultimately turning your head away from the ball is asking for trouble..... There has only been one other death in 1st class cricket from this, so it does need putting in perspective even though it is so tragic.