“On the flipside of that equation, a great beer that has wide distribution can be taken for granted, only to be highly valued once it becomes a rarity. That was the case with Cantillon. “It was what the geeks nowadays would call ‘shelf turds.’ It was everywhere. But Cantillon isn’t on the shelves anywhere anymore, and so what was extremely common 10 or 12 years ago, is now hard to find,” Simpson says, noting that nowadays some people will trade multiple rare beers in order to get their hands on one of them.”

Matt Simpson talks about collecting beers,
In How do Craft Beer Collectors Calculate the Value of a Beer?
From Fusion.net