I own 300+ unbuilt model kits all of which are sitting packed away in boxes, I guess that would qualify me as a collector? I'm not a hoarder I am just waiting for time and space to build them. I have some experience building models and I have always bought my models with the intention of keeping and building them but sometimes my interests change and I sell off the ones I no longer want. From a seller's point of view I would admit that I would be happy if my item sold for more than the price I paid for it but truthfully I always aim to break even and if not oh well.
There is a collectables and toy store at my local farmers market and the owner is a scalper / hoarder. He sells a lot of Transformers, GI Joe's, Star Wars toys, Matchbox cars, Comics and so on. The majority of items in there are marked up to twice the price of retail (at least). Every time I go in nothing changes much I do not see many people buying his stuff. Even if the guy is able to sell some of his highly marked up toys it takes him a long time to make a sale. Yes it irks me when I cannot find the toys / models at my local supermarket or hobby store and the scalpers have it and are demanding crazy prices but at the same time I can find what I want online usually at below retail prices if I go for used / second hand.