Consumerism feeds itself these days. We're all guilty of it. I see two main factors here:
1. Nobody makes things that last anymore. It's not the fault of the manufacturer either - it's a result of market forces. The reality is that a $25 DVD player that you have to replace every other year sells better than a $100 one that'll last you 20 years. The $100 one is EASILY cheaper in the long term when you factor in replacements or repairs, but the reality is that very few people do that.
Also, very connected to this situation, is the fact that the repair business is gone. It used to be that if your TV or something broke, you called someone to fix it. However when you compare a $15 repair to a $25 replacement (even if it is a piece of junk), people have proven time and again that they'll buy the junk replacement. I've seen this countless times with computers. People will throw out an entire computer and replace it due to a bad hard drive or power supply, or even worse just a corrupted Windows install that would take an afternoon's time and no actual money to fix. Tons of equipment that works fine, or could be made to work fine with a few simple repairs, ends up in the landfill every year.
End result of all of this though is that people keep buying replacements for products that they have already bought before.
2. We've become a people of hobbyists and collectors. Trust me, I'm probably as guilty as people can get in this area, but the reality is that we buy multiples of items we only really need a few of because we're interested in them. I've got 40-ish guns. To have 1 for every specific purpose, I really only need 5 (a .22LR, a centerfire, a shotgun, and a handgun). Push come to shove, I really could get by with just the shotgun if I had to. Computers - I really only NEED one, but I'm a hobbyist there too. I've got 4 desktops running at home (Windows 7, Ubuntu Linux, Mac OS X, and HaikuOS), along with 4-5 more that work but aren't setup, and a laptop. Guitars? I've got several of those too and I really only need 1.
As far as collectibles I've also got lots of that stuff that I don't really need. Painted figures/statues, comic books, collectible card games, etc.
It's a trend that I'm TRYING to ween myself away from, but it's hard. Honestly though, I really think that our economy is going to HAVE to adjust itself eventually. The cheap imports won't last as their currency and labor prices go up, whilst our money's value comes down. We're going to have to start making some stuff stateside again. Other countries wont' just keep shipping us containers full of stuff to sit around and provide services to each other. And with domestic industry coming back, prices will rise. An economic collapse will result in some people making less money. However, we WILL make due. Housing cost is a reflection of local economy. As the country as a whole makes less money the price on that will come down to match. I think we'll make it, but there's going to be a rough adjustment period until things balance out.