Random fact of the day: There are more unemployed Psychology graduates than any other degree subject (if you want to walk out of university and straight into a job then currently topping the most 'in demand' tables are Sciences and Engineering).
I mention this as I know nothing about psychology, but I do have an area of expertise in video games. Last night I was playing Skyrim, and the thought occurred to me that developing my characters stats and equipment in a role-playing game shares some key things in common with developing my Star Wars collection. It's a similar kind of satisfaction. Adding a fire enchantment to make my sword better = adding instructions to make my boxed Ewok Battle Wagon better. Searching through a dungeon and discovering a rare artifact = searching through a collectors fair and discovering a rare Lili Ledy figure. It's the satisfying feeling of steady improvement that keeps me coming back to Skyrim, and it's the same reason that keeps me building my SW collection.
I don't know if I've hit on something fundamental here, or if i'm just a guy who stayed up too late gaming.
What do you guys think, and i'm not just talking vintage Star Wars here, but a broader universal question - why do collectors collect?