I think I know the answer- there are thieves out there.

When a friend of mine retired to Sequim, Washington, from Juneau, Alaska some years ago he brought me a Mason jar FULL of plectrums. Don't tell me he BOUGHT them all.

I busied myself for two months handing them out and I STILL have a small bowl full.

I must admit that I have never gotten back my favo(u)rites so he evidently didn't get them all. There must be more thieves out there.