Actually E-ink contrast is very good if enough light reaches the E-ink display, the problem is that to add color to an E-ink display you need to add an LCD laye

Actually E-ink contrast is very good if enough light reaches the E-ink display, the problem is that to add color to an E-ink display you need to add an LCD layer to it so you can change the colors. Many e-readers then also add a digitizer for touch screen capabilities. Each of these layers added on top of each other reduces the amount of ambient light that will reach the E-ink layer reducing the brightness of the white parts of the display, thus lowering the contrast. To compensate for this you need to add LED lighting to illuminate the display which increases eye strain and requires adding a diffuser layer which, you guessed it, lower the contrast. Compare an e-reader from back in the early days without all these extra layers to a modern e-reader and you'll see just how much the contrast has degraded over the years if you don't have the LED lighting turned on.