Since no-one knows what was going on in Sol while the GTVA was cut off, there's no telling what happened, I see INF being as good an idea any, I've never been one for nitpicking, as long as the game is fun and well executed, it doesn't really matter where the EA Fleet came from etc.
Take Twisted Infinities as an example, it's on hold while I'm at Uni, but far from dead, and it's set 11 years after Capella. There's stuff that happens in TI that doesn't tie in with Inferno at all, does that make TI wrong and INF right? Of course not, it just makes them two different takes on continuations of the same story.
Don't get me wrong, Inferno is definately worth a play and is a great Mod that shows all the hard work put into it, but a lot of hard work goes into other Mods as well, and I just feel that labelling Inferno as FS3 isn't fair on them, and might actually deter them from finishing.