I think its more what you are doing. A raid in an extremely difficult place to even get into without aggroing something that will wreck you instantly then you might grab a backup but I'd imagine for the other 95% you will be doing naked corpse runs. No one wants to run to the bank to equip a second set, run to retreive their corpse, then go back to the bank to drop the second set off so they aren't encumbered, before going back yet again to rejoin/join a group.