Oh, really? In order to "pop on and confirm/deny" they first have to know the discussion is happening. So, now they have to *monitor* EN World? That certainly has a cost in time and effort. And what about the other sites out there - does WotC now have to declare some sites as officially supported? How many? Start multiplying that monitoring cost - you're now talking about having "online communications coordinator" being a job description....
Any time you find yourself in the position of thinking, "Well, they could just take a quick look at it..." (where "they" are anyone working in a professional capacity - doctor, car mechanic, public relations coordinator, or what have you) you are probably underestimating the amount of effort supporting that kind of service actually takes.
Didn't they just hire someone for a community relations position?
Checking on fan sites and maintaining a presence should fall under that. Although, having the name designers pop in should also be encouraged.
Looking in on ENworld is a good idea. See what the fans are talking about, what problems they're having with the game, how they're using the system, what questions they have, and more. In addition to surveys, a Twitter, and convention conversations, it's a way to stay in touch with the fanbase.
You cannot just communicate by letting the fans talk to you. You have to actually do the legwork and approach the fans. You have to respond to their comments and questions, or even answer their questions before they're asked.
The D&D community isn't *that* huge. Monitoring ENworld and RPGnet would be enough. Many posters manage to do that just fine, sometimes even daily, to say nothing of the mods. Are the WotC staff less busy then us? Their time is so precious they cannot spare an hour every other week?
For example, jury duty. We had to inquire into the state of something (conversion guides) before they told us it was delayed. And there haven't been a lot of updates. They didn't volunteer that information when they were sure there was going to be a delay; they kept silent until someone noticed and pressed.