Many creatures in nature collect what they see as scarce resources. If it might make their lives easier or better or just more fun later on, they’ll drag it back to their nests.

If I were living out in the wilderness in a cabin with no modern amenities or contact with the outside world, what would I do? If I had enough food, water, etc. to last me for a bit, I might wander the forest for 8 hours. Let’s call this my work day. Perhaps I pick up 3 shiny rocks and a really cool stick. This would be my pay for the day of work, yes? So if I pay for a Nintendo DS or a Video Card or some other materialistic object for my own enjoyment, that’s my day’s work.

A human creature whose needs are satisfied will fill their time by collecting objects for their own enjoyment, like a raccoon hoarding bits of shiny metal. “Materialistic” people do the same thing that any animal will do, and I really don’t see anything wrong with that. As long as one’s needs are met first, why not have fun with the rest of your abstracted money/time? It’s only natural!