Because of the weight of the particles that are being moved. They have to shake them, move them a bit, shake them again, move them a bit again. Moving a blob of

Because of the weight of the particles that are being moved. They have to shake them, move them a bit, shake them again, move them a bit again. Moving a blob of plastic takes a lot more energy than what LCD's do: who just moves something like 1 electron per 10000 in the layer between the polarization filters. The way multicolor e-color displays work is by having multiple size/weight particles that are moved by different field strengths, but require being even more careful (because every field, shaking and moving, will move every particle)