Did you read the description and design discussion accompanying it? To consider it like the first wave of playtest - not even polished playtest a few iterations in. It looks like more effort went in than to an article, but still within the neighborhood. It got something with some semi-official blessing out there to build on (and probably to also judge interest) at a time when people are complaining about lack of new support. It's not supposed to be a polished Eberron document.
Fair enough, which is why I didn't complain about it when it was released. I genuinely appreciated (and still do) the bone they threw us. It's only an issue in context with the "we're focusing on the Realms" comment. Together, that makes it feel like there really isn't a plan to do any more and they can use it as a technicality to dodge the pitchforks of Eberron fans.
In fairness, there may be additional context that's missing. It could be that they're short-staffed enough that they've only got the pipeline to work on one setting book at a time (almost certainly true) and they want and intend to work on another setting after that release, but they're too heads-down to really make a commitment on their next project.
That I get. I'm a software developer and I get hammered all the time about what I'm going to work on "next", when I'm still trying to plan out the current six-to-nine-month project.
If that's the case, I get that. Personal feelings aside, the Realms are the most popular setting and will sell the most books. Cool. Carry on. I'd like to see the adventures more generic, but I've also advocated that each setting release comes with a single, tightly-coupled adventure to get folks going on it.
That's not the way I understood it, though. The quote sounds more like they're going to have some level of formal support for the Realms, but won't be revisiting other settings until/unless something changes. Evidence from HotDQ indicates that the third-party adventures will be pretty hard to decouple from the Realms. If the internal effort is also focused on the Realms, then it's not just a matter of no setting getting first-class treatment, but of one setting taking all the resources to the point where not only do the other settings get left in the cold, but DMs who want to home brew (the norm, IME) lack support.
In this case, it's not just a matter of prioritizing limited resources. It's that, but it's prioritizing in a way that I believe is detrimental to the game. I'll change my behavior in such a way as to most effectively send that message (i.e. reduce the fiscal viability of the proposed course) and would encourage others to do the same.
Again, if they're going to have reasonably setting-agnostic adventures, my statement doesn't hold. The priority should be 1) home brew or generic setting, 2) basic support for best-selling setting, 3) basic support for premier (i.e. sufficient to break-even or turn profit, with the idea of encouraging core/generic sales) settings, 4) deeper support for higher-profit lines. FWIW, this is why I think a reimagining of Dragon and Dungeon, with occasional hardcover releases, would be the best support model.