If you read the story, you will notice that he wad UNABLE TO TRIGGER HIS AIRBAG!!! but his wife was able to trigger hers. All of the clients on that trip had airbags. How does this make an airbag better then a beacon??
Who here is putting an airbag as being "better" than a beacon? The airbag gives you a POSSIBILITY of it saving you instead of hoping that someone else saves you later. but nobody is saying not to wear a beacon because you have a bag.
As to him not pulling... do you REALLY think that every person who straps a bag on has the presence of mind to pull it when the SH** goes down??? HELL NO!
Take into account that they were custy's on that trip, and the bags were not theirs, so I doubt it was something that they practiced like most of us practice reaching for our triggers (for a guy who talks about the importance of practice... I'd think you'd see that factor) so I'm not terribly surprised that one pulled & one didn't. What does surprise me is that guides still allow more than one person to be in danger on a slope.
I hope SBD DOES use stories like this to sell more bags & increase the awareness that this is one more tool that CAN, not guaranteed WILL, save you when every other mistake has been made. More bags sold = more chances that a friend won't be the guy that we see dead on the news.
It's not a be all end all, it's another tool in our quiver.
As to the story you posted... there's no guarantees in this game, nothing but you can prevent the worst from happening. For all we know, that guy could have pulled right before it stopped & there wasn't time for it to bring him up... who knows.