Out of curiosity.

[Arohk]

...I'm not sure what kind of answer you're looking for, but the very obvious one is: Because storing data costs money. So they limit the amount of data everyone of us can store.

I hate to say it, but WoW has a fantastic system when it comes to glamour collection, once you owned an item it is stored in your collection and can be used for glamour, instead of physically owning the thing.
The only difference here is that WoW can't dye items, so im not sure how that would work out.