Perhaps Mad could comment, but I suspect that these aren't collected so much these days anyhow. I don't think there are the dedicated collectors that used to exist. Something is only valuable as long as someone else wants to buy it.
Look, you've got it all wrong! You don't NEED to follow ME, You don't NEED to follow ANYBODY! You've got to think for your selves! You're ALL individuals!
Yes! We're all individuals!