As one who has a business that uses eBay a lot, I have a love hate relationship with the giant. Love, because it is indeed an entry to a global marketplace, hate, because the charges are exorbitant and help for sellers nearly non-existent. Would I leave given a chance? You bet. I wouldn't even pack my bag. Like thousands of other eBay sellers, I closed my store last year, when fees were more than doubled overnight. Since then service has continued to decline and costs have continued to rise. In one insane incident I have several books removed because I listed them at 0.99c with postage and handling charge of $8. Oh terrible sinner. Eventually eBay removed the trading violation from my record, but would not admit they were wrong to remove the books in the first place. I just happened to have two titles that I got very cheaply and I put them up as a good value opportunity for my buyers. Now I am not predicting eBay is going to disappear overnight, but rather that the all powerful one is very vulnerable to competition. If say, Google rolled out a good value auction site, there is a chance they could blow eBay out of the water.
But then again, do online auctions have a long term future? Maximising seller returns is the basis of my PhD study at the moment and preliminary data I have collected has certainly changed my selling strategies. For another angle on challenges for eBay see EBay: Evolution or Hibernation by Jeffrey Young on ZDNET.