Don't forget after Dubai (that is not shorter, is only the marathon in the World with the best opportunity of time, when the weather, like during the last two years, is perfect) Desisa and Tola ran another marathon : Desisa winning Boston, and Tola going for 4th in Paris.
At top level, it's not possible to run 3 marathon in 6 and half months. May be 2 marathons in 2 months, but after the second athletes need to have time for recovering, before rebuilding their qualities of strength and speed at the base of a top result. Marathon at this level is not only endurance...
Stephen Kiprotich won OG last year because his marathon before Olympics was not finalized (was considered a "passage" on the road to OG), and was in February (Tokyo, 2:07:50 on 26th).
Instead, Wilson Kipsang and Abel Kirui had to compete in "Trials" in London (22nd of April) at their top shape, otherwise were not selected.
So, don't forget in Uganda there are no selections, but athletes as Stephen or Jackson Kiprop are in the team for sure, and can prepare looking at the championships only.
The same happened with Abel Kirui in 2011 : he dropped out from London because sick, and was able to start the full preparation from 10th of May with the nervous tank completely full.
Apart Dubai, Kebede is the most consistant athlete who was today in the race. But after two marathons such as Chicago last year, and London this year, he could not recover his best shape, and struggled after 30 km.
Anyway, Stephen is now very much stronger than last year, and is at the same level of the athletes with a PB under 2:05:00. He's also a very humble person : when we were in London this year, and he had some problem before the race for a car accident, he told me "I know I can't win, but I don't look at the position, I want to improve my time, because I've still a lot to learn".
In London he ran 2:08:05, after falling down in a refreshment having a strong impact between one knee and the ground. When started running again, with pain, he decided to finish without pushing too much, for having another experience, and immediately after told me "I want to go Moscow because my Olympic Gold without some confirmation is not so good".
So, the big difference between him and Kenyan / Ethiopians was he WANTED to compete at top level, because WCh were the main goal of the season. Instead, Kenyan / Ethiopian were selected without real interest to have the best possible training for the event, and many of them ran against their will.
About the personal best of Stephen, we can see something really interesting next year, because there are no Championships in summer, and he can have the best chances both in spring (London again ?) and Autumn.