[GeoffR]

In many countries outside the US Sony have a big advantage over other brands: they have the only e-ink reader that can download Adobe DRM epubs directly from the public library system. They seem to sell quite well in New Zealand despite the Sony ebook store not being available here, and despite being near the top of the price range for ereaders. I suspect the ease of borrowing public library books is a big factor in that.

Edit: So for business reasons it might make sense not to bother competing in a market where they have no advantage to support the higher margins they can attract elsewhere.