This new theory is almost two weeks old and I have to say it has some merit to it.
The summary of the theory is that because of the time travel that is sure to happen in Avengers 4, Nick Fury has known precisely what was going to occur in the MCU up to that point. The theorist, Reddit user u/sfmarch07, gave some legit support including some little details from The Avengers.
You can read the theory in full below:
My theory doesn’t so much pertain to specific things that will happen in Avengers 4, as much as it deals with an overarching idea of the MCU that will culminate between Captain Marvel and end in Avengers 4. I’ve taken elements of my theory from other common theories I’ve seen around online. My theory basically is that along with the time travel element that the movie will have which has been widely speculated and the Avengers needing to retrieve the infinity stones from different points in time to fight Thanos, additionally there is going to end up being a huge element of “everything happening for a reason” that will encompass everything that has happened in the entire MCU up to this point thus far.
What I mean by that, is I believe Nick Fury in the 90’s in the Captain Marvel movie will be shown or made aware of the future and future events, potentially even by Dr. Strange coming back in time from Infinity War, and he will be shown specific things that he and other characters have to do throughout the entire MCU to ultimately set up future events for how they need to be in order for the Avengers to win in Avengers 4, per Dr. Strange’s end game plan from the possible 1 out of 14 million outcomes. Meaning everything that has happened in MCU so far had to happen the way it did but more importantly was set up in certain cases to happen the way it did partly by Fury himself.
If you go back and watch most of the scenes and post credit scenes with Nick Fury in the MCU movies, it’s like he always knows something that the other characters don’t, and knows how to tell them just what they need to hear or he contributes something that makes a big difference with no explanation of how or why he knew to do it, from recruiting Iron Man, Hulk, and Captain America, to in Iron Man 2 when he gives Tony his fathers box. Or like at the end of Thor 1 when he instructs Erik Selvig to work on the cube. Or in Age of Ultron when he shows up out of nowhere in the barn and then pushes Tony and the team forward to where they ultimately create Vision with the mind stone.
If you go back and re-watch the nuke scene from Avengers 1, right when Tony goes through the worm hole with the nuke everyone at Shield celebrates except for Fury and Maria Hill, instead they look at each other and they look down/dejected. You’re meant to assume they’re sad because they might have just lost Tony Stark. But the movie intentionally doesn’t show Fury’s reaction when Tony comes back through the worm hole. My theory is they act the way they did because they know that Tony going through the worm hole is the real beginning of the Infinity War/Thanos timeline, and it will lead to Tony’s PTSD and everything that not only Tony does after that point but also sets in motion everything that happens in the MCU after that event, eventually leading to and including Thanos’ snap and the events of Avengers 4 . Fury and Maria vehemently tried to stop the nuke from being fired during that scene, Fury even shoots down a jet on the carrier, because it was like they already knew the Avengers would close the portal and win the battle without the nuke. But I think Fury knew that the nuke going through the portal would alert Thanos of Earth’s capabilities and make Earth a target, and it would also make Thanos aware of who Tony Stark, like he says in Infinity War.
If Fury was shown the events of the future back in 1990 during the Captain Marvel movie and was shown things he needed to do for the future, that would also explain why he started out as a lower level guy in Shield who was ready to hang it up according to the Captain Marvel trailer but ends up becoming the director of Shield by the events of the first Iron Man movie in 2008. During Captin Marvel, Nick Fury learns about aliens and cosmic threats for the first time, which is his true motivation for assembling the Avengers in the first place. And I don’t think its a coincidence that Tony Stark is the first Avenger that he recruits either, which is the other part of my theory. I think in Avengers 4 through some of the time travel that will happen, you’ll be shown or alluded to how all the events in the MCU up to this point have been set up and happened the way they did for a reason, including especially the events of Civil War which was also written by the Russo brothers the same as A3 and A4.
Which leads me to the other part of my theory, which revolves around the importance of Tony Stark, and also in part the soul stone. I think in A4 the Avengers will try and retrieve the stones from different points in time as has also been heavily speculated. In order to retrieve the soul stone though, Tony is going to have to sacrifice something, the same way Thanos had to sacrifice Gamora. But instead of sacrificing Pepper Potts, what if Tony instead has to go back in time to 1991 and infiltrate Hydra or seek out the Winter Soldier, and order the hit on his parents himself, sacrificing the thing he loves most, to enable him to get the Soul stone to fight against Thanos, knowing all the while what it will cause in the future and all the anguish it will personally cause him along with the events of Civil War, breaking up the Avengers, and everything that happens after that. Or maybe Nick Fury back in 1991 tells Tony that he has to do this. It would be the hardest decision that any character has had to make in the entire MCU, and a decision that only Tony Stark himself could make, a burden that only he could bear, truly exemplifying him as “Iron” Man. I don’t think its a coincidence either that Captain Marvel takes place in 1990 and Tony’s parents are killed in 1991. In fact the actor who portrays Howard Stark in Civil War has already been reported to be returning to play Howard Stark in Avengers 4. Then Nick Fury agrees not to recruit younger Tony until he’s ready after the events of Iron Man 1 in 2008. This would create a time loop sort of or a causal loop or bootstrap paradox in the MCU timeline, without necessarily needing to change anything in the past or re-writing the timeline, it sets up more of a “which came first, the chicken or the egg” type scenario, because I don’t think Marvel Studios would spend 22 movies setting up all of these intricate stories to just then go back and erase them or re-write the timeline in Avengers 4. And this time loop could ultimately be a big part of Dr. Strange’s end game plan to ultimately defeat Thanos and undo the snap, just like he did against Dormammu.
Oh and I think it would also be cool if when Tony and ant man travel back in time to the battle of NY from Avengers 1 as the leaked set photos have shown, if Tony told Captain America not to sign the Sokovia accords no matter what, further setting up and adding deeper meaning to everything that happens in Civil War.