I would have to disagree that a short course guy could adapt to desert quicker & better then desert racers could to short course.
Taking away all the logistics in a desert race, which we know is way more involved & intense vs. a short course race. A strictly short course racer has one or two races a day that are approx 10 to 15 minutes long. Their focus and adrenalin is concentrated in that short amount of time. Once again besides some ruts the track is groomed and much more predictable vs a desert course.
If you look at the history of short course or stadium circuits, most of those races were and are desert racers. 75% of the racers in the Mickey Thompson series were also racing Score/HDRA.
Today, look at how many desert racers are racing short course vs short course guys racing desert. Here is a list of good desert racers who are good short course racers that I though of real quickly;
Rob MacCachren
Jerry Whelchel
Carl Renezeder
Jeff Geiser
Justin Davis
Marty Hart (Former desert champion)
The Leduc family
The Coyne family
Justin (Bean) Smith
Cameron Steel
Doug Fortin
Jason McNeil
Greg Adler
Larry Jobs
Pat Dean
Show me a true short course driver who has come out to the desert and won races? I'm sure there have been some, but not as many that have transitioned or double dip from desert to short course.
My vote is still Dakar Rally for the most skilled driver. Way to many things you need to be proficient in to be even able to finish a Dakar Rally.