Galen had a great race. He's a very talented runner...for a non-African. I think expectations of what he can accomplish have been completely unreasonable, especially on this board. People posting things like "Farah = Rupp" based on some stupid logic that they train together and that they have been supposedly neck-and-neck in work outs is utter rubbish and total hype (likely perpetuated by AlSal and Nike).
Rupp simply doesn't have the aerobic ability or the finishing speed to beat the top Africans on the world stage. Everyone was salivating on this board when he closed a glorified tempo run 10000m at USA's in 1:52. Now if he could close a race like the WC 10000m in 1:52, that would be something...he would of won the race (he was 25:20 at 9200m) but he can't and won't ever be able to do so.
Does this mean he should move up to the marathon? Maybe. But even if he does he will still lack the endurance to win the big races and beat the top Africans.
My advice to the USA if they want to win distance medals: Start importing athletes from Kenya, Ethiopia, and other east African countries and make them US citizens (a la Lagat). This is the USAs best hope for success in distance running in the future.