Here's what it boils down to: We're entering the fourth anniversary year of Webb's incredible 2007 season. That season was FOUR years ago this summer. In those four years, he hasn't even been relevant on the national stage, let alone the world stage. He's failed to make two national teams in that time, and in one didn't even run the finals of the selection race. And he doesn't exactly have great odds to make this years WC team, either.
Whatever his problems are (and he's been chronically injured) they've now reached the point that he's faced with a very daunting task. Consistent world-class performance requires consistent world-class training. And "consistent" as used here means years, not week or even months. Be inconsistent long enough and you get a situation where you have to back way up and just start over.
There may have been someone that I can't recall, but I cannot think of a single runner who has fallen that far and stayed down that long who ever got back to their previous level.
But then again, this is Alan Webb. He's alternatively dazzled and dismayed us for ten years. For Alan's sake, I hope that he finds solutions to whatever the issues are that have prevented him from performing up to his incredible potential. I have no idea if this coaching change is a good idea or not. I just hope it works for him.