Might be a mental thing as well... If you ride 5 mile loops for hours then you are still against the wind for large parts of the loop. You don't really get that much of a mental boost. ...and you get no benefit the following day.
If you ride 180 miles into a headwind, in the knowledge you will have consistent wind direction for the following day then you know you get the chance of fast, full days tailwind blast. It must have been a nice feeling waking up this morning knowing he had done 'the hard work' yesterday. Earning himself little boosts like that may well be the kind of thing that keeps him going over the year(and a half)
Steve is out and back everyday, self supported so he doesn't get as many tailwind days as Kurt ..that's not a knock of Kurt ... its just reality.