On Inventory Space

Are we back in the time of Rogue? Why do MMORPGs these days insist on having inventory space? Even ultima Online and Diablo has some decent inventory management (The former using item weight on a free sorted inventory and the latter having items occupying different space depending on their size). Playing MMORPGs these days, one would be inclined to believe that armors and rings have the same size (Ring mails have thousands of rings in them, shouldn't they occupy thousands of inventory spaces?).

Let's try to find out why inventories are set as they are today. Technologically, it is easier to manage an inventory that has a fixed number of tiles, but not so much that it has to be the de-facto choice. It is much easier for players to manage items in a fixed-tile system, of course, but it also affords less room for players using a lot of small items (potions, trinkets and one-use items).

Ultima Online has a very loose inventory system, giving players maximum flexibility; duping exploits aside, it is much closer to real life inventory management. It's harder on new players, of course, but not so much that it counterbalanced the added advantages. If Origin managed to do it back in 1997, why can't Blizzard, SOE and NCSoft do it again nearly a decade later?