Is eBay still as Interesting to Instrument Collectors as It once was?

Unfortunately, the answer to that question seems to be a resounding "NO!" An informal survey of my collector customers suggests that far fewer "interesting" instruments have been offered on eBay of late when compared with the offerings of only a year or two ago. Most of my collector customers approach Ebay watching the same way I do - I actively maintain a 10-day book mark list of items of interest. The average number of items on my personal moving bookmark list over a month can be considered as quantitatively characterizing how interesting Ebay is to me during that month. Until perhaps two years ago, my 10-day bookmark list averaged some 20 to 50 items, but more recently only 10 to 25 items - i.e., eBay is less than half as interesting to me now as it was only two years ago. I think that feels about right, as do many of my collector customers, and it raises some serious questions. Has the majority of previously undiscovered quality instruments finally found their way into the hands of advanced collectors or, are more sellers now choosing to offer their highest quality items through private sales rather than through eBay auctions? Finally, is this apparent downward trend on eBay likely to change in response to the recent restrictions announced by the major auction houses regarding their future sales of antique scientific instruments? Comments welcome.