Rupp is a track runner. Smooth on the oval with International class times and closing speed. Why would he shift focus to the marathon when he is world class competitive at 10k?
Someone mentioned Ben True and I agree this guy could be our next top American marathoner and should move up now. Great cross country runner with low 13:00 5000 speed. But he'll probably not go to the marathon until he is in his 30's and over the hill like Tegenkamp and Kennedy.
For an American to win a WMM it would have to include a runner who is world class at both 5000 and 10000, a runner who is currently a favorite to make International teams at those distances, to take that gamble. Like Ryan Hall and Ritz. And by the age of 25-7. Guys that were capable of making 2-3 Olympic teams on the track and maintaining a great living by doing that without moving to the marathon,.