Well, the first-ever e-ink reader was issued in Japanese market. So, for a short period of time Japanese did lead the market.
It was
Sony Librié.
Look it up.
It as a spectacular failure.
Sony didn't let people to load their own content. The only books you were allowed to load up were those you had purchased in their on-line store. And those expired after 90 days. Such aggressive DRM was too much even for Japanese market.
When Sony saw abysmal sales, they released utility that let you publish your own content for Sony Librié, but it was too late ...
The firmware, and labels on buttons were only in Japanese, so it was unusable outside Japan. Much later there was complicated way to "root" the device and load English menu, but for rooting you had to navigate Japanese interface.
To be honest, the prices of books [so I was told] reflected the fact that you were in fact just renting them for limited time and not "buying" them. Not that you are buying ebooks even today, for other readers, in other stores but that is a different story ...