People who do not understand the underpinnings of programming should not be trying to speak with authority on this. It's a memory limit on the PS2, there is only a finite amount of memory and that memory needs to contain EVERYTHING that is needed at that moment in time. This includes animations, sound and music data, zone data, character data, npc / player data, map data along with the engine code itself. That all has to fit within a 32MB allotment, go over and you'll trigger an exception which crash's the code. To facilitate the demands of a MMO on a console with limited resources SE has hard coded limits on everything. Each line is a couple of bytes, not much really but when your looking at such tight memory limits you realize they would have to remove something else before they could extend it.One obvious reasoning for Square Enix design choices and shortcomings is that they are trying to run the network communications conservatively with their server so the networking costs and server loads are manageable.
This has nothing to do with sever limitations, inventory data is so tiny and is only loaded once when you zone. Get rid of the PS2 and suddenly your memory hard limit becomes much manageable.