IMO, this is a basic RPG mechanic. You get a bag you can fill with stuff. Bag gets full, you get no more stuff. Empty stuff from bag to get more stuff. Sometimes, devs choose to make it so you can't move or something else instead, sometimes you just can't get any drops. Each rpg does it differently, FFXIV lets your stuff fall on the floor. The end result is the same, the player needs to learn to manage their inventory.