There are few true Black hole collections. Mostly, I think, because of the financial aspect of keeping every single piece of OA purchased.
Conversely I think there are many micro-black hole collectors. Pieces may come and go, but they have that small selection that will be the last pieces to go if/when they begin to divest.
I can't find a feature on CAF as a whole to look at pieces by date posted, but that link is in each individual CAF gallery. How many pieces were posted in 2000 that are still in the same collection? I'm guessing quite a few. So, for a majority of the board members here those pieces have been locked up before they even thought of entering the hobby. So, anyone looking for any of those pages is out of luck.