As the new generations come, the colors can expand but I don't think it is time for the 9th gen to get its own color or be expanded by any color, expanding it quickly for every new gen definitely gonna make colors more worthless.
Once we hit the next generation you'll get a color. There's a total of 6 colors striped across all the generations so as we increase the colors get put onto more generations. Right now it's moving towards one color per two generations but eventually, it'll move further (ie. one color used by three generations).