Technically, all that info is likely stored at the server (some may be mirrored and synched on the client periodically, but ultimately, most if not all is stored at the server)....the issue is when the items to represent them have to be loaded into memory at the client level. There is only so much room reserved on the PS2 for KI and normal items. There is only so much bandwidth they can reasonably expect to use when reconciling these items between the server and client (remember, this has to support both PS2 and Dial-Up access). Probably less about server-side optimization and more about client-side platform limitations and expected server/client bandwidth issues.