Why Diablo 3 is less addictive than Diablo 2

Out of necessity, Diablo 3's reward system has to account for the Auction House. Because equipment is never destroyed, in-game rewards can never be too frequent or powerful or they will flood the Auction House, eventually trivializing game difficulty. There have been many solutions proposed, but the reward system seems so intertwined with the Auction House that it's difficult to see a radical change coming. Blizzard's response over the next few patches will be very interesting to watch.