E Ink announced a new version of their Kaleido color displays. Named Kaleido Plus, the new screens have the same color reproduction as the first generation but bring improvements in screen assembly and the front light that improve the overall picture and color saturation.
https://www.notebookcheck.net/E-Ink-announces-new-Kaleido-Plus-color-displays-with-brighter-colors-and-bigger-screens.527218.0.html
Hmmm... it's quite decent now.
The problem with coloured E-Ink is that today everyone is getting used to HRR OLED smartphones that can display everything and have a battery that lasts for two days. And the price of these display seems to be comparable.
Colourful E-Ink could also have it's uses in low-power applications, or for semi-static images, but since it's already way behind the curve, the tech will probably remain niche - and therefore expensive.