Teresa Nielsen Hayden has written an amazing, heavily linked, well-researched piece on the Color Marketing Group, a trade association that determines each season's "in" colours and dictates the national pallette.
I knew what was up with the big khaki push. Remember that one? Ads everywhere saying "Hemingway wore khaki"? We'd all been wearing black for several years. We had black levis, good black skirts, black leather or denim jackets, little black dresses—a great installed user base of basic black clothing, plus the colored stuff we wore with it. I hadn't heard anyone sighing for the return of khaki, and if I had, I'd have pointed them to one of the WASP mail-order catalogues. What's the big deal with khaki? It gets dirty too easily, and for a lot of people it's an unbecoming color. But there's only so much new black clothing you can sell a happy consumer who already has a closet full of black-and-coordinates; so the clothing industry pushed khaki remorselessly.