In the Dangerous Discussion forums people have lately started saying Starfield will kill ED. X4 will also kill ED. And SC. Its basically whenever there is any hint of any game being vaguely related to space, people will start saying it will kill ED.
Ah, I see. Well, we know how it turned out previously on every occasion, so... yeah.

I haven't actually visited Dangerous Discussion for couple of weeks, now. So it's me who's out of the loop. Hell, if Elite dies, I won't even know it!
Source? I'm way out of the loop.
No particular source of this, only what is apparent from their interviews and tidbits of information.
They clearly stated that their new IP (Starfield - I still think it's more of a project code name rather than actual name of the game) is a priority for them. They said it when they were asked about The Elder Scrolls VI. They said that they want to focus on the new IP first, before the next TES game.
From that, most of the people deducted that Starfield is what's coming next (possibly this E3) and then the Fallout 76 came kind of out of nowhere. So logically, I assume that on this E3 they're going to announce Fallout, then a year or two after that we will get the Starfield project and then, maybe five or more years from now, next TES.
In any case, E3 is almost upon us and we should have some solid info soon.
