He had his 59:43 3 years ago (age 24), and his 2:06 2 years ago (age 25). I'm not knocking ANY of his performances, but it must be said...he is not the great white american hope that everyone thought he would be. I can't see him actually "competing" with any of the top tier guys with times like: 2:12:33, 2:09:40, 2:08:41, that he has put up. Great times, but nowhere near 2:03/2:04.
His 63:55 only reinforces the fact that his frail body is aging and can't keep up with his age 23/24 year old body. He might put out another 2:05.high/2:06 within a year or two (at most) but I can't see him going under 60:00 again or running a 13:10 5km. In my book he is done.