Well take the extremes of the collectors on this site and not that different. How many folks sport 300+ blades while mumbling something about SHTF, or guns, ect - I think hobbies can transgress into obsessions relatively easy and they represent an attempt at escape from real world life. This is incredibly common in society and I wouldn't really go out of my way to point out the preppers as somehow different or more mental than anybody else. Take extreme golfers - yeah that idiot who gets up at 4:30 am, three business days a week to get his tee off time and has the $1000 clubs and crocodile skin bag to match them. Now take the more normal, yet every bit as extreme, consumerism of the every day North American. This extreme consumerism (folks pouring over the weekly advertisements to see what new deal on the latest electronic gidget, or new phone or new IPAD, folks who routinely buy everything on credit so they can have it now etc.) is considered norm only because it is highly encouraged by market forces and peer groups. Extreme preppers spend their time and money on flawed things with a flawed argument and pass these problematic behaviors to their kids. Extreme consumers, the more common psychological problem in society, spend their money on flawed things (in hopes it that new purchase will put their needs to rest) with a flawed argument and pas these problematic behaviors to their kids.
Judge not, lest thee be judged I say.
+1 I'd say part of the driving force behind storing food etc. and hoarding knives or stamps or cars or etc..... is similar. All that is required is a justification. It can aptly be referred to as a hobby. When that hobby interferes with other aspects of our life then it can be referred to as an obsession.