HYDRA's ultimate plan in Captain America: The Winter Soldier would have changed the MCU as audiences know it by killing most of Earth's superheroes. In the 2014 film, Steve Rogers uncovers how HYDRA had been operating inside SHIELD since the organization's birth. Apart from controlling world events from the shadows, HYDRA had a plan to use SHIELD's helicarriers to fire at thousands of targets all around the world to eliminate every potential threat and establish themselves as a force to be feared. However, for all the plan's ambition, it had several fundamental flaws and may even have doomed the entire universe.
Thanks to the combined efforts of Captain America, Black Widow, and Falcon, Project Insight was stopped before it was too late. Most of SHIELD's helicarriers were destroyed, and the Winter Soldier found himself freed from HYDRA's control. However, had HYDRA succeeded, every single event from that point onward would have been altered – and the results would have actually been worse, not only for the Avengers but for HYDRA as well.
Project Insight would have essentially eliminated current and potential threats to HYDRA, but things might not have turned out as well as they imagined in the long run. The helicarriers had enough firepower to go after most of the Avengers and even kill Stark if he was unarmored, but dealing with Thor and the Hulk would've been a whole other matter. Also, HYDRA would have had to deal with a possible Wakanda intervention in response to their takeover. Most of all, if HYDRA managed to take every obstacle down and defeat the Avengers, the entire universe would have been doomed as Thanos would arrive on Earth years later with only a handful of enhanced humans on his way. Here's how the MCU history would have turned down had Project Insight worked.
HYDRA's Project Insight Would Have Killed Most Of The Avengers
During the events of Winter Soldier, the Avengers lineup was still the same as it was in 2012. After defeating Captain America and Black Widow during the film's final battle, HYDRA would have to eliminate Iron Man, Hawkeye, Thor, and Hulk. Although the last two would need special treatment, Project Insight would quickly kill Stark and Barton. The very concept of Project Insight was based on catching the heroes off guard, meaning that Tony would have been easily killed without his suit and that Barton would not even have a chance. With Captain America and Black Widow perishing in battle and Iron Man and Hawkeye killed by Project Insight, four of the original six Avengers would be dead within minutes of HYDRA's takeover. Given the shape of the MCU after HYDRA's defeat, it's safe to say that the death of these key players would have had huge consequences for the rest of the saga as audiences know it today.
HYDRA Would Still Have To Deal With Thor And Hulk
Even in an alternate universe in which HYDRA comes out on top, the group would still have some serious problems. In this scenario, four of the six Avengers are dead, and the team essentially no longer exists. Even still, HYDRA would face a significant challenge to deal with: what to do with Hulk and Thor. For the Green Goliath, after the firepower of SHIELD's helicarries most likely failed to kill him, HYDRA would have to utilize the other ace up their sleeve: the enhanced twins. As proven in fight against Iron Man in Age of Ultron. This would ensure that HYDRA did not become an easy target for the Hulk, and other governments and law enforcement agencies around the world would be forced to help contain the emerald giant. HYDRA wouldn't be able to kill the Hulk, but they would make him much less of a problem, thanks to Wanda.
As for Thor, HYDRA would have to be very patient. The timeline of the events of Winter Soldier and Asgardian attack led by Thor. However, considering that Midgard wasn't being threatened by aliens, let alone by aliens with ties to Asgard, Thor would not get the authorization to gather a garrison to take to Earth. If Odin was still in charge, he wouldn't want to intervene so significantly in a local conflict. If it was already Loki disguising himself as Odin, that would be one more reason for Asgard not sending help. In other words, Thor would be on his own.
HYDRA's primary weapons against Thor would be Loki's Scepter, Wanda, and Pietro. Once Thor decided to interfere by himself, HYDRA would use the firepower of the helicarries to overwhelm him, and then Pietro and more skillful agents could lead a more direct attack using HYDRA's retrievered Loki's Scepter. Taking Thor down would be impossible, so HYDRA would have to walk him into some mental or energy trap set by Wanda. Unable to kill the God of Thunder, HYDRA would keep Thor in Wanda's prison as long as they could. In the meantime, HYDRA would continue to work on creating more enhanced beings.
How Would HYDRA Handle Wakanda?
Even if the Avengers were successfully neutralized, HYDRA would also have to start worrying about the rest of the world's governments, including Wakanda. At the time of the events of Winter Soldier, Wakanda was still secluded and did not take much of a side in United Nations affairs. However, if Project Insight had worked, King T'Chaka would have had to step up to at least ensure that HYDRA would not make a move against his country — which would be considered a threat by HYDRA given Wakanda's technology and Vibranium storage. That said, both this new HYDRA-led United States and Wakanda would have enough firepower to cause massive damage to the other, meaning that any military action would be very well thought out before being taken.
Considering King T'Chaka's isolationist politics, Wakanda would choose not to be directly involved in the HYDRA situation. Likewise, HYDRA wouldn't pick up an unnecessary fight. Thus, a cold war would be established between these two forces. Wakanda would continue to exist as an isolated country, and HYDRA would have one less thing to worry about, at least for a few years. King T'Chaka would never be assassinated as the events of Age of Ultron, and consequently, T'Challa became king and Black Panther.
HYDRA Winning In Winter Soldier Would've Doomed The Universe
The consolidation of HYDRA's power and the death of the original Avengers would mean that the team of heroes that opposed Thanos in Avengers: Infinity War would have never been formed. Instead, the only weapon HYDRA would have against the Thanos invasion would be enhanced ones like Wanda and Pietro, which HYDRA would have continued to experiment with. Essentially, HYDRA would have its own Avengers team made up of enhanced and super-soldier variations. However, the key to defeating Thanos — or more precisely, to preventing him from completing his plan to wipe out half the universe — wasn't just sheer strength but rather a particular set of variables.
Not even a combination of the powers of every single available Avenger was enough to stop Thanos from snapping his fingers in Infinity War. The heroes were taken by surprise while Thanos had all his moves already planned. Even if HYDRA had a team of enhanced warriors whose power rivaled that of the Avengers, something that would be difficult given how it took them two years to give powers to two people only, the most this team could accomplish would be to delay Thanos just as the Avengers did. Thanos won in Infinity War and only didn't win in the end because Doctor Strange was making every move based on what his visions of the future had revealed. Stephen Strange and his exceptional use of the Time Stone would be a resource that HYDRA wouldn't count on, mainly because Strange was one of Project Insight's targets already during his time as a surgeon.
For that very reason, Captain Marvel, who's stronger than Thanos when he hasn't got the Infinity Stones, wouldn't be able to stop the Mad Titan from wiping out half the universe. Once again, Thanos' attack was swift and accurate, and Captain Marvel was only warned of an emergency happening on Earth by Nick Fury when it was too late. Similarly, in this alternate timeline, Thanos would prevail over HYDRA's defenses, gather all of the Infinity Stones, and perform the snap. The most Captain Marvel could do would be to get revenge, but without Iron Man and the rest of the Avengers to put together the time heist plan, plus not having Doctor Strange at all, saving the lost lives would be out of the question. Essentially, HYDRA's takeover in Captain America: The Winter Soldier would be disastrous for the MCU in its entirety.
