As someone pointed out the other day on the Golf Channel coverage, this is kind of trajectory is not unheard of among pros. Even just in recent years, there are several examples of people being near the top of the world rankings, falling sometimes hundreds of places, and climbing back up.
One such example is Henrik Stenson. Sure, no one cared much when he fell off the face of the Earth because he's never won a major, but he showed that you can be a top 10 player, fall out of the top 200, and climb back up.
So, when we know that Tiger did great even in years after the scandal, and we know that other golfers have "lost it" inexplicably (and subsequently regained it), it doesn't make sense to blame the scandal.