This is a myth, endlessly repeated without a source. Not only have the original patents expired, but there's a competing tech called Display Electronic Slurry (DES, or the cofferdam tech).

The real reason e-ink hasn't seen much innovation is that it's a tiny niche market, because e-ink is useful for e-readers and not much else. In contrast, LCDs are produced at a rate of billions per quarter, which gives room for lots of companies to compete furiously.