1 million switches for a pixel is about 5.5 hours at 50 Hz, assuming the worst case of a state change on every frame. Surely it can't be that bad for larger panels? The existing e-ink monitors from Dasung and Onyx would have had problems by now.
I imagine most people are using those monitors for text-based applications, which have a much lower rate of pixel change. Still - the pixel switch lifetime is currently a limitiation of eink.