That is entirely true. And I had spent a long time looking at ePaper devices. Unfortunately, the devices I was looking at turned out to be far more expensive than comparable tablets, and with ePaper you were locked into only reading books. (Or view web pages, email, etc, assuming they even provided that functionality). I didn't want to be restricted to just books, so I went with the tablet instead.
Some company in India actually came up with a design similar to what you describe. I forget the name now, but they called the display a Qi Display. The last time I looked into it, there were issues with quality, so I stopped paying attention.