I have a small theory. When things are going poorly in a society, people reflect this by wearing dark or very muted colors. Recently, I've noticed that the number of dark colored cars far outweighs the brightest colered ones; I would say by an 85 to 15 ratio. This is just a rough estimate as I certainly haven't carried out any proper count.
Similarly I've noticed that dark colored clothing is much more popular than brighter stuff. And this is at a time when technology has made it much easier to produce bright colors for nearly everything we use. But it's not drawing many buyers. Why is this? My theory is that in spite of being told that everything is getting better, people can tell that they are not improving. Hence a need to become less flamboyant and leaving the bright seventies type clothing in the back of the closet. It's a shame, I think.