A recent DPRK documentary pointed out that while a monochrome society used to be one of their explicitly propagandised goals, over the past decade they've become much more colourful. (under the influence of chinese tourists?)

There was a marketing theory I ran across back in the twentieth century, that societal colour palettes change in predictable ways. IIRC it was something like clothing is the first place a palette changes, then cars, then home appliances. But my memory is not the best.

The opposite reasoning from dusty white cars occurs for witches: they always have black cats, because who wants to always be cleaning white fur off the robes and pointy hat?

"Never drive black cattle in the dark."