I never said that the IMCO killed longboards, but the fact that longboards almost died while the IMCO was in the Games, and then revived very soon after, is interesting. Sure, it could be just coincidence, but are we sure?
Like a lot of these sort of discussions, maybe all that's demonstrated is how complex it all is? I stuff it up by coming across as if I know the answers, but a lot of the time the whole point is that maybe none of us do.
Stats on other Olympic classes are interesting; I have in the past checked them for France and Germany. You may be right, I may be coming from an Anglo-Saxon viewpoint and can be forgetting that some of the Olympic classes are (sometimes due to official policies) quite popular in some areas.
BTW in places the only places that had existing indigenous production skiff types (UK and Aus) the 49er is less popular than the B14, its older, slower, smaller, non-Olympic stablemate. But yes, it did get into other areas because of its status.
The thing that often gets me is that this is probably the sort of thing that should be formally and openly studied by ISAF.