If the goal wasn't time or place why didn't he choose something like the half-marathon instead? A marathon beats up your legs and requires lots of rest afterward whereas a half-marathon can be used more like a workout. If he did a half, he could continue training towards Tokyo and not have to do two separate blocks.
I understand he wanted to come back after a disappointing London, but I don't understand why he's run a non-competitive marathon that frankly no one really cares about. He's not proving anything by running a 2:04 and not racing good guys.
Discuss.