The article simply (and, one might argue, rather effectively) shows data; the comments here have been far more interesting.

This seems to be a surprisingly polarizing (pun not intended) issue. Why are some people sanguine with the diminishing of color, yet others find it upsetting? Why is it a fashion trend to some, yet a crucial piece of identity to others? I don't know, but I'd love to find out.

So here's my addition to the brew: urbanization. What if the trend is not entirely fashion or economy, but also a function of population density? I've spent my fair share of time in both urban and rural areas, and the urban seem to be much more chromatically homogeneous in terms of surface area, punctuated with more vivid splashes. Rural areas tend to lack the sudden bright splashes, but have miles upon miles of subtle variation. Could increasing population densities be contributing to a loss of color?