I can think of a way or two Potco may come back. It IS possible it will come back when Disney gets their next truckload of cash. This is really only the clues for someone in denial it's gone forever right now. But looking at how popular Pirates of the Caribbean was when it first came out compared to other pirate movies, it just might. (Think Pirates got popular because of the mix of Pirates and Voodoo) But last I checked, the third Pirates movie was the most expensive movie on the planet, I think, so if they end up spending more than they receive, Pirates won't come back. If it's a big hit, Pirates Online will probably come back better.
