More paid sales are the end results of less shill bidding. That benefits both buyers and sellers. Fanatics IP bans non-paying buyers. Fanatics also removes potential non paying buyers/shill bidders during an auction. Ebay does neither.
As for ebay showing data, here is a 100% bid activity account with an astonishing 5,000+ bids, in one month, all on one seller:
This type of bidder would have most likely been banned on Fanatics. They are still active on ebay.