Being from Michigan, I wasn't in L.A. to see Marty Tripes win the first "Superbowl" of Motocross. But, I was in Daytona the first year they built a track on the infield of the racetrack. I was also at JFK Stadium in Philadelphia for the first stadium race held east of the Mississip. I'm hip to the differences. I guess I'm just an old school kind of purist. I pretty much agree with what you've said, other than motocross just being endurance. Over the years, supercross has crept into outdoor tracks. Most have man-made whoops, or doubles and triples, tabletops, rythem sections, ect. So, to top off having 40 minutes worth of endurance, a rider has to deal with hitting his marks.
But, with all the man-made stuff that's become the norm in motocross, the gnarliest jump in all of motocross is provided by Mother Nature. The up-hill triple known as LaRocco's Leap at Red Bud.
Rrreeeddddd Bbuuuudddd!!!!!!