— is buying a car in a ‘colour’ more expensive than buying one in grey, black, silver, or white? It must be cheaper for the car manufacturers to have only a few colour-ways.
— is it easier to touch up a car that is not a limited colour?
— is it a vicious cycle where more people bought black/white/grey/silver cars so companies started producing more of those colours?
— is it easier to resell a car in a basic colour-way?
— do black/white/grey/silver have fewer accidents?
— are leased, rented, or fleet cars more often black/grey/white/silver?
— are these colours more classic and therefore less likely to look dated in a few years?
— are they less prone to fading?
I have noticed home decor has become more beige in recent years so it could be part of that trend, although motorbikes really do come in every colour of the rainbow.

Morning Janet
Regarding car colours. Imo white cars are easiest to sell, coolest in summer, easier to touch up, easier to clean, although a variety of different whites.
All the garish and bright colours are found in rental cars as I am sure they pick up all the cars in garish colours that the manufacturers cant sell because of the strange colours, and get them at cheaper prices.
My opinion for what it is.
Hope all well.
Jack