I don't think that anyone in Frontier is deliberately witholding information regarding Elite IV. They're not a company in the size of Rockstar or EA that can devote several team members to developing one game and several others to another game. All their time, energy and effort is devoted to The Outsider.
That said, I'm a little intrigued by seeing the PC Gamer interview from back in 2004. It seemed to me that DB already had some clear ideas about what he wanted from that game. It would be nice if he could confirm whether any of those ideas will be included (if possible of course

).
In the worst case scenario with Elite IV becoming even more vapourware than Duke Nukem

, I would be disappointed, extremely disappointed. However, without the enjoyment I got from playing FFE I wouldn't have bothered to join this forum. I didn't join because I wanted to find out about Elite IV; I hadn't even known there was one "planned" all those years ago. I keep coming here every day, not because I hope to see some news on Elite IV (it has already been mentioned, several times, that The Outsider is everything; once that is done then Elite IV can begin), but because I like reading what the other forum members have posted. There is a sense of community here that isn't present on the majority of forums I have joined.