3D printers aside (I don't know enough to comment), literally everyone I've seen who claims e-ink is held back by patents is either 1) speculating or 2) repeating hearsay and can't provide a source.

Regardless of the issues with patents in general, in the specific context of e-ink it's an unsubstantiated myth until someone provides some hard evidence.

E-ink patent speculation is especially problematic because everyone on HN agrees that patents are a problem, so it sounds truthy and people want to repeat it as an example of the evils of patents.