I'm one of those guys with the 300 (395 to be exact) streak that's at about six days right now. So in answer to your question
If it happened to them, why couldn't it happen to me?
A: Of course it can happen to you.
Of course, it could also not happen to you. But who cares? We have a goal, we want to be clean. We all have at least one reason for it, most of us probably have many. So just because it can happen, maybe even very likely happen, or even
did happen, isn't the remotest reason not to try to stop right now.
I personally don't think that it has to happen, it takes a lot of stupidity to fall after a very long streak. (did I just insult myself?) After a long streak it gets much easier and you're already in the habit of being clean. In addition to that, after a long while of being clean you get a taste of what life without it is about and that itself is a boost to help you get up again.
I think that seeing people like me on the bottom of the chart can be discouraging, and disappointing, but it also serves a purpose. First of all it serves as a lesson to remember when you Be"h get on top of the list that you aren't invincible (Hey inna, try to remember that next time k?), also I think that seeing someone with a long streak at a few days can be a big chizzuk. If a guy with such a long streak fell, yet he still thinks it's worth giving it a shot, then how can anyone say it isn't?