Illuminating observations, zippyfusenet. It hadn’t fully coalesced in my mind before, but now that you’ve said it I agree. I’ll have to keep that in mind in future.
It doesn’t bother me much to paint the same thing on several different figures in the same colour. On the other hand, what does bother me a bit is when disparate items that would logically be made of different materials, crafted by different processes or sourced from different makers are all painted the same colour. Often when I look at painting guides or tutorials, one of the final stages is something to the effect of “…and then I picked out the pouch, the scabbard, the canteen and the coil of rope at the figure’s belt with Army Painter Banshee Brown”. Me, I have a pathological need to paint each of those things in a different colour, even if they’re all just variations of “earth tone”.