Sylvie

they are sold in packs of 81 in order to convince the wasteful mind that they don't need to be treasured. this train of thought goes on until they lose all of their earring stoppers. then they have to buy more.

An intelligent person should not have to buy more than one pack every 20 years. If this is how everyone thought, there would be no money made on earring stoppers. so people have to be influenced to be wasteful and uncaring about their "practically unlimited supply". before they know it, they are due for 81.