The Avengers team considered going back in time to 2988 BC in Avengers: Endgame, which would put them at the center of a significant event involving an Infinity Stone. Marvel Studios was able to revisit several major moments from the Marvel Cinematic Universe thanks to Avengers: Endgame's time travel plot. The Battle of New York in 2012 from The Avengers, Star-Lord's trip to Vormir in 2014 from Guardians of the Galaxy, and Thor's time on Asgard in 2013 from Thor: The Dark World all served as essential parts to the Avengers' plan.
The goal of the team was to travel back in time using the Quantum Realm and take the Infinity Stones so they can reverse Thanos' snap in the present. While three time periods and four teams were ultimately what were chosen, the Avengers (and the film's creators) considered many other options. One of them was going back to 2009, but another one of their alternate plans appeared to include going thousands of years in the past.
A blink-and-you'll-miss-it moment in Avengers: Endgame when 2014 Nebula helps Thanos to future shows the details of other coordinates the Avengers entered into the Quantum Tunnel platform, with one of them being 2988 BC. That year predates any of the main storylines that MCU films have explored, but is when Thor: The Dark World's opening takes place. This suggests an alternative method the team had to acquire the Aether, aka the Reality Stone.
The prologue of Thor: The Dark World shows the fight between Asgard and the Dark Elves for possessions of the Aether. Malekith, the leader of the Dark Elves, had control of it and was ready to use it the Reality Stone during the Convergence. Before he had the chance to unleash the incredible power, the present king of Asgard at the time, Bor, and his Asgardian army arrived to hold him off. The Asgardians then used the power of the Bifrost to transport the Aether away and left it hidden for the next few millennia.
If the Avengers did consider going back to this point, their aim surely must have been to obtain the Reality Stone. The alternate plan could've been to have Thor pose as an Asgardian warrior in this battle to find the Aether and retrieve it with Rocket. It's debatable, but this may have been an easier way for both Thor to get the Reality Stone and for Captain America to subsequently return it - instead of injecting it back into Jane Foster.
But while this could've been a potentially easier time for Thor and Rocket to visit, it would have stripped the God of Thunder of some meaningful moments that come during their 2013 trip; while on Asgard, he reconnected with his mother and learned that he needs to be who he really is, not who people think he should be. Additionally, he wouldn't have received confirmation that he's still worthy and could wield Mjolnir.
All that considered, it's likely that moving away from the 2988 BC time travel destination was made with the story of Avengers: Endgame and Thor's arc in mind, more so than when it would be easier in-universe to get the Reality Stone.
- Black Widow (2020) release date: May 01, 2020
- Eternals (2020) release date: Nov 06, 2020
- Shang-Chi and the Legend of the Ten Rings (2021) release date: Feb 12, 2021
- Doctor Strange in the Multiverse of Madness (2021) release date: May 07, 2021
- Thor: Love and Thunder (2021) release date: Nov 05, 2021