In reply to bouldery bits:
Well of course there are collectors of art, old cars and antiques etc. But collectors of old climbing books? Do such people even exist? Surely only climbers, and pretty keen long term ones at that, would even appreciate a book on Wolfgang or Extreme Rock. And I imagine most of those are far too busy actually going climbing than to be bothered about paying a grand for some old books on the subject. It's just such a participant oriented sport it seems to me that few people have such a strong (ie. expensive) need for nostalgia.
I remember cherishing my Master of Rock (John Gill) book in the eighties. I lent it to someone and of course when I asked for it back they couldn't find it. I was gutted. Back then it was irreplaceable - impossible to get another copy. I looked online recently and found one for £25. I was very tempted but in the end I didn't buy. Had it been half that price I think I would have bought though.