Weren't many course originally built as ways to land squat?
With the accelerated rise in land and housing values that occurred between 1999 and 2005 what better time to unload, then sometime in the last five years? At least from a long term (and perhaps a little hindsight) perspective.
So, won't these numbers have a certain bias that may or may not point to the games popularity? (If'n that's what Joels after)
As an aside, How many G.C. would/should there be if the number of serious golfers (50+ rnds/year) was considered to be the total market? 5-7 million golfers...?