>>eBay could completely change the rules and make it much more like an actual honest-to-goodness auction by extending the auction until it's received no bids for a period of time, say 5 minutes. Until they do, the best play is a good end game.

If Ebay changed the rules it not be anymore like an auction. It is an auction, just a different type. There are many types of auctions that end at a specified time.