It was mostly copper and gold colors in the beginning of the graphic. Then they found same ways to apply colors to objects. And we can't say anything now about

It was mostly copper and gold colors in the beginning of the graphic. Then they found same ways to apply colors to objects. And we can't say anything now about if Color has been disappearing from world. The data and graphic is not complete. It could be demand and demand can change with time. People may be bored from black and grey in future and all the object colors would change.