While there are almost surely economic forces that incentivize colour choices, as others have pointed out, and the article points to a gradual trend over time .

While there are almost surely economic forces that incentivize colour choices, as others have pointed out, and the article points to a gradual trend over time ... I think fashion trends tend to swing in both directions as well. I remember the 80s being colourful and vibrant. Big hair, bold colours. Especially in women's fashion. Then the 90s pulled back from that quite a bit. Hair styles got flatter and straighter, colours toned down. In the 00's I remember 80s fashion starting to come back a lot. The last 10 years have been felt grey and "flat" again.