I guess a lot of people just woke up to Galen Rupp? I remember hearing about him doing TOUGH workouts after races his freshmen year at Oregon, that was almost 10 years ago. I know a lot of guys who talked about this back then.
I forget exactly what the workout was, but after he fell down in a 5000m race and got back up to run 13:50 he was out on the trails or another track doing a full blown workout.
I believe the same thing after he ran his 28:15 weeks later.
This stuff is not new. In fact the way I heard it described was that his workouts were insanely tough back then and indicated much more than his racing level/pr's at that time.
Assuming that he already started doing this in high school, it's not all a stretch that the workout after race thing is just second nature at this point. It's also not much of a stretch to assume that in his early years this would have taken a bigger toll on him, leaving him flatter during races and unable to kick as well. But after 8-10 years of it and hitting his mid 20's, well that is precisely when this long term investment starts to pay dividends.
There are probably a few times when he doesn't think about a workout afterwards, and those are international championships. I think in there minds everything up to then, is just prep. No matter how important an AR or WR attempt at and indoor 2 mile record may seem to most of us, to them it's only important if it doesn't take them off track with the bigger goal.