Where I'm at, it appears those who had brass chose to take advantage of the shortage to sell. In addition, nobody leaves their brass behind, anymore, other than someone with a new firearm, for example, who may leave a box or 2 behind. Others, who would normally have ignored spent brass have realized there is a market & scrounge everything for reselling.
Personally, I lucked out by being overseas for an extended time. My stash was intact & still had primers from when they were $15 a thousand, to include Berdan.