The main reason is that most of great jazz collectors died, and their sons are much more interested in money then in vinyl. I personally know a guy whose father was one of the main italian jazz critics, his collection was around 15,000 original pressings. The only problem for me is that the son is a good and talented jazz pianist so, no way to put my hand on the collection. Maybe I gonna make him an offert he can't refuse. As soon I'll find a horse's head.
Hey Porcy - welcome back !