Part of the problem is the Internet. The bottom fell out of the rare book market and probably many others.
This is true. Now "rare" collectibles, like books, are much more easier to find and get thanks to the internet. I once had a collection of rare books and movies on VHS. I sold them on eBay (the eBay site was still brand new) when they were still considered rare items. Now those same movies and books that I sold for a fortune can be had for a really small price.
I don’t know if it is a problem. What happened was people found there were more copies outstanding than they had thought. In other areas the opposite was true.