After the Infinity Saga, only three original Avengers remain in the Avengers: Endgame saw the defeat of Thanos (Josh Brolin), marking it as the end of the first storytelling chapter in the MCU. To further drive the idea, it also functioned as the swan song for Iron Man (Robert Downey Jr.), Black Widow (Scarlett Johansson), and Captain America (Chris Evans) arc. This, however, left the future for the other key characters doubly uncertain.
Both Tony Stark and Natasha Romanoff sacrificed themselves for the greater good; the former gave up her life to acquire the Soul Stone in Vormir during the time heist, while the latter wielded all six Infinity Stones to defeat Thanos once and for all. Meanwhile, Steve Rogers was given the chance to retire — although specifics of his final fate remain a mystery. As promised to the Ancient One (Tilda Swinton), the Star-Spangled Avenger was chosen to return all six elemental crystals to prevent unwanted branches of time. He then went further back to the late '40s to reunite and live a full life with his one true love, Peggy (Hayley Carter). It's currently unknown where he is, but the idea is that he's no longer around. That leaves Hulk (Mark Ruffalo), Thor (Chris Hemsworth), and Hawkeye (Jeremy Renner) from the original lineup who's still active in the MCU.
The franchise is currently in a transition period, with MCU Phase 4 promoting its second generation of heroes to be its next primary characters such as Scarlet Witch (Elizabeth Olsen), Doctor Strange (Benedict Cumberbatch), Sam Wilson (Anthony Mackie), and Captain Marvel (Brie Larson). There is a string of new faces that have ed the franchise such as Shang-Chi (Simu Liu) and the Eternals, among others. Additionally, a third batch of players is also poised to debut as the more direct replacements for the original Avengers. Ironheart (Dominique Thorne) and Yelena Belova (Florence Pugh) are set to assume Iron Man and Black Widow's vacated mantles. And while Hulk, Thor, and Hawkeye are still in the universe, they, too, have their respective successors in She-Hulk (Tatiana Maslany) Jane Foster (Natalie Portman), and Kate Bishop (Hailee Steinfeld). This is a reminder that sooner or later, the final founding will exit the franchise, although it's curious how.
Hulk
The She-Hulk, not to mention the rumored World War Hulk film, the Avenger still has a relatively long future in the MCU.
However, once that's all done, it's curious how Marvel Studios will write out Hulk from the franchise. using Pym Particles so he'd explode from the inside out. But, that seems too gory and violent for live-action. Instead of killing the Hulk, he could simply be retired, similar to how Avengers: Endgame wrote out Captain America. That way, he could live in peace, as he always wanted. Perhaps he might even be able to settle down with a love interest. This way, the MCU is still able to easily bring back the character if the story calls for his involvement.
Thor
Like the Hulk, it's quite difficult to craft a satisfying send-off for Thor simply because he's essentially an immortal. As someone who has lived for more than 1500 years, he can still continue being an integral hero in the MCU, dying of natural causes like his dad, Odin (Anthony Hopkins) in Thor: Ragnarok instead. The difference between him and the former Allfather, however, is that the God of Thunder has no plans of settling being the Asgardian King. His conversation with Frigga (Rene Russo) during the time heist in Avengers: Endgame allowed him to finally realize that at his core, he's no king, but a natural adventurer. This means that as long as his physical body allows him to, he would much rather be a wandering warrior than a sitting king, which is also a more dangerous path.
Frankly, at this point, there's really no rush to write out Thor from the MCU. Among all the remaining founding heroes, it feels like the God of Thunder’s real arc is just beginning. Part of that is because it took Marvel Studios a while to figure out the right approach to the character thanks to Taika Waititi's involvement in Thor: Ragnarok. Given that, it's best to age out Thor in the franchise instead of finding a way to send him off. After all, as an Asgardian, he's certainly able to be around far longer than his peers. He can function as the franchise's elder statesman. Hemsworth doesn't need to always be buff for the role, as he grows old with Thor, he can mellow down and be just a guiding presence instead of a frontline hero. Then when the time comes, he can also naturally die the way Odin did.
Hawkeye
As early as Avengers: Age of Ultron, Captain America: Civil War. When he showed back up five years later in Avengers: Endgame, he had already taken a new ruthless persona as Ronin as part of his grieving process over the death of his wife and kids due to Thanos' snap. But when the idea of the time heist came up, he came back to his heroic roots and reed Earth's Mightiest Heroes.
ittedly, not everyone is thrilled about Hawkeye's fate in Avengers: Endgame. Instead of Clint sacrificing himself for the Soul Stone, which could have been his penance for his misdeeds as Ronin, Black Widow ended pulling off the sacrificial play. Now, he continues his narrative, training Kate Bishop in Hawkeye. Similarly, the mini-series could have served as the swan song for the character. Here, Marvel Studios had the opportunity to make up for Nat's controversial death in Avengers: Endgame by seeing Clint also sacrificing himself either for a good cause. That didn't happen as the hero survived the events of the Disney+ series. However, Marvel Studios can find a future opportunity to hold him able for his going on a rampage as the samurai vigilante, killing as many people as he was able to. Perhaps Hawkeye could even die saving Nat's sister, Yelena, who made an appearance in Hawkeye as his final heroic act in the Marvel Cinematic Universe.
