Reading the LetsRun article on Reed Fisher and him running the Houston Half, it shows he has a half marathon PB of 62:06 and has not run very many races, not even a full marathon yet. And he only got some sponsorship this year!
What's more, Fisher is now in a proper training program with the Tinman group that works on his 5k and 10k speeds working out with the other team mates during the weekdays and only doing long runs on the weekend. Compare this to Walmsley's haphazard speed work and over training with way too much useless mileage.
Jim Walmsley has a half marathon PB of 64:00 and has run a lot more than Fisher. I bet you Reed Fisher is going to pound Walmsley into the ground at the Olympic Trials.