The collecting impulse relates to retentiveness and the desire to hold onto things and order them rather than throw them away. Like a genetic disposition towards height, this shows up both as an individual predilection and as a general trait in homogeneous populations. I'd like to make a bold natural selection interpretation of why some cultures have larger stamp collecting instincts than others. Across the world, philately seems to have a direct relationship to latitude. The closer to the poles, the more likely a culture is to have embraced philately. This has often been explained as a factor of economics as Northern European countries have traditionally been among the world's wealthiest. But many national groups closer to the equator have enjoyed economic success in the last fifty years and they don't seem to be embracing collecting hobbies. I think colder climates, with their long winters, have produced a psychological instinct to save because it is just such saving that helps them through the long cold winters. Food must be put away stored canned. Heating materials must be obtained- the entire unconscious structure has a profound emphasis on putting away to preserve for a later, colder day. In cultures where the climate is always warm, where food grows all the time, wealth and education may proliferate but there is no underlying consciousness of saving the little things that won't be available over the long winters. Certainly our modern world has made such a mind set unnecessary (and may account for some of the decline of philately) but as an unconscious driving force behind philately this theory has much to recommend it.
A Theory on Collecting