> most of the ebook world is leaning towards smaller screen sizes

These are seriously niche devices. They're currently trendy but the Kindles of the world probably have something like 98% of the market.

Yes, but except for the Scribe, even the Kindle readers are too small!

Kobo had an 8" ereader. People loved it (except for the battery life). But there's no sign they'll make more of them.