SE doesn't want to put most of the profit FFXI generates back into FFXI, I doubt they even roll 10% back into the game.

With that kind of budget, creating a new system to save BLU magic & PUP sets would take a long time, so much in fact, we still haven't seen it after they announced they were working on that last year. or was it the year before last? i don't remember.

A new system for non-inventoy storage slips would take a similar amount of DEV time. not worth the investment.