Inventory in most games is considered "Prime real-estate" meaning that players always want it, and will PAY for it. Games put items in their game to inspire players to collect and even horde these items as means of digital wealth, marks or their accomplishment, or as a means towards a goal. Players trade, buy, sell these items, so having the space for it, is something they want.
Now most games start you off with minimal space, and then expect you to acquire more of it as time goes on. In DDO, they simply sell us the space, and why they keep such a well of wealth untapped, is beyond me.
Additional space in this game is a win for everyone.