Well maybe it's as simple as this. Black text on white (or silver) or white text on black, presents the most contrast and therefore the greatest readability. There is a lot of print in very small font on many panel fronts. The manufacturers are trying to make their products easy to use. Any manufacturer will weigh the relative commercial value of usability versus the attraction of an unusual color scheme. Which is undoubtedly why the trend is away from unusual color schemes.
But don't mind me. I'm just an old fuddydud engineer.