I’d say no. Not long ago I saw an HN user who debunked the theory that E Ink is holding the industry at gunpoint with “the patent.” Forgot his name, but he seemed to work in the monitor/display industry. It seems like it’s just a myth; nobody who claims the theory is true has been able to provide substantial evidence.

Yes, although the original patent expired in 2017 so it's a little less clear-cut nowadays. They do have hundreds of patents and bought up basically all non-Chinese competitors though.

Regular old trade secrecy is also a big factor I think. I look for interesting new EPD papers on scholar.google from time to time, and they tend to be about stuff an undergrad would think of in the first twenty minutes, which suggests to me that everyone is trying to keep their tech very much under wraps.

Patent holding E Ink is a myth