Yes, it has. Even purely from the consumer facing side: the latest panels are far better in grayscale depth, sharpness and refresh rate (and their controller still kind of suck). Not to mention colour e-ink panels in consumer products seeing rapid improvements gen over gen.

> and no sign it will, as it's controlled by one company.

That's less true today, and there are multiple implementations of this idea that are being commercialised.

Though, sadly, e-ink the company bought one of them...