They were more than happy to discuss what kind of direction they wanted to take with Fallout, until they discovered the loudest fanbase that a franchise can be "graced" with.
They talked about what little they could at the point of the license being acquired, which only makes sense. People would be interested to know what the plans are and so forth. As we saw from the interviews at the time, there wasn't much that could be talked about for a variety of reasons (mostly because it was too early), so it's logical that the game has somewhat faded into the background.
I doubt that the most vocal of the FO fanbase has anything to do with why nothing is being said about the game right now. Oblivion is Bethesda's "flagship" game right now, and the one furthest along in development. Once that's done and out, I'm sure FO3 will be getting lots of attention.