Even if this callback didn't happen, the choice between Falcon and Bucky as the new Captain America should've been a no brainer for Steve. This isn't because Bucky is not a "good man" in any way, but rather simply because Sam is better equipped to take on this role.
Why did Falcon become Captain America instead of Bucky?
During that time in the Marvel Universe, Steve Rogers was still around, though he had lost the Super-Soldier Serum effects and had rapidly aged. As a result, Falcon was chosen by Steve to wield the powerful Captain America shield in his stead.
Because the strong man who has known power all his life may lose respect for that power, but a weak man knows the value of strength, and knows compassion.” This is also why Steve chooses Sam to be the next Captain America.
Summary. Bucky Barnes's absence in Captain America: Brave New World benefits Sam Wilson's story, allowing the Marvel movie to focus entirely on the latter character. Sam Wilson deserves to be the sole focus in his first Captain America movie, and not have attention pulled away in favor of Bucky Barnes.
Bucky Barnes, like Steve Rogers, has lived for several decades due to cryogenic freezing and the super-soldier serum. Bucky's life expectancy could potentially surpass Steve's 116 years, depending on circumstances. Despite outwardly aging at the same rate as Steve, Bucky can still live for at least another 80 years.
Sean Kanan aka Mike Barnes Talks Cobra Kai Season 6
How old is Bucky biologically?
Taking the experimentation, cryogenic freezing and time skips into consideration, Bucky is physically somewhere in his mid-30s by the time The Falcon and the Winter Soldier takes place, making him appear seventy-some years younger than his chronological age.
Bucky owes his youthful appearance to repeated cryo-freezes orchestrated by the Russians. He possesses no super powers and never received a form of the Super Soldier Serum as many assume, but continues to operate at peak human ability.
Barnes' personality and memories proved difficult to fully suppress, so they put him in cryogenic freeze between missions. Still, he was credited with over two dozen assassinations in the span of 50 years. In 1991, Barnes was thawed out and sent to retrieve Howard Stark's new attempt at the Super Soldier Serum.
Summary. Captain America: Brave New World promises to explore the stories of new and canonical characters, including Isaiah Bradley, in the MCU. The absence of Bucky Barnes allows Sam Wilson to shine as he takes up the mantle of Captain America and reassembles the Avengers.
Bucky had resentment towards Sam for giving up the shield. The therapy session showed the issues they had towards each other. Bucky wanted to know why Sam gave up the shield that Steve trusted him with and was Steve's whole legacy. Bucky emotionally says that if Steve was wrong about Sam then he was wrong about him.
Despite giving Bucky eight hours with Zemo, the Dora Milaje eventually came for him, which led to Bucky fighting those who aided and supported him so much. This naturally resulted in the Wakandans seeing Bucky as a traitor, specifically Ayo herself. Wakanda is not wrong to be angered by Bucky's actions.
Why is Bucky not strong in Falcon and Winter Soldier?
As a villain, it made sense to present the Winter Soldier as unstoppable, to make him a better foil for the heroes he fought. With his reformation comes an increased vulnerability; physically weakening him helps the audience better identify with him and ensures he can't simply knock out opponents with one punch.
Bucky tells Steve Rogers a shocking truth: the Outer Circle was responsible for the murder of his father and his conscription into the military. In short, his entire life was shaped by the Outer Circle, and Bucky desires revenge.
It's also what he wanted for Steve. Like anybody that ends up traumatized by a war experience, he was affected by it for the rest of his life. So, what felt like a desire there was for a restart - for him and for Steve in a way. It didn't necessarily feel like the shield was gonna be that.
After returning the Infinity Stones to their original timelines, he remains in the 1940s with his lost love Peggy Carter; they marry, and Rogers lives a full life. Rogers chooses Sam Wilson to be his successor, passing his shield and the title of Captain America onto him.
While at the HYDRA Siberian Facility, Barnes' prosthetic arm was destroyed by Tony Stark's unibeam, after Stark was manipulated by Helmut Zemo and attacked Barnes and Steve Rogers.
James Buchanan “Bucky” Barnes enlists to fight in World War II, but eventually literally falls in battle. Unfortunately, the evil Arnim Zola recovers him and erases his memory, turning him into a highly-trained assassin called the Winter Soldier.
In the Guardians of the Galaxy Holiday Special, which released before Guardians of the Galaxy 3, Nebula gives Bucky's arm to Rocket as a Christmas gift.
We see that he's deprogrammed 6 months before the snap in FATWS. He's then snapped away and comes back 5 years later. FATWS takes place 6 months after he comes back. So Bucky is likely 33 physically while chronologically being 107 (FATWS takes place in April 2024, so Bucky's wrong about being 106).
Bucky Barnes' love interests are few and far between in both the MCU and the comic book pages. One of the few serious relationships that Bucky built outside of the MCU was with his love interest Natasha Romanoff.
The actor also said that Sam and Bucky's relationship is rooted in acceptance, appreciation, and love for each other. "You'd call it a bromance, but it's literally just two guys who have each other's backs," he said.
The Winter Soldier Program was a top secret HYDRA project started by Arnim Zola in the 1940s to brainwash American soldier James "Bucky" Barnes, whom he had administered with his own version of the Super Soldier Serum, and turn him into a super soldier assassin known as the Winter Soldier.
Even Bucky's variant serum should allow him to age normally (unless he gets frozen again). A side effect of the Super-Soldier Serum that the Winter Soldier shares with Captain America is that neither can get drunk.
What happened to Bucky Barnes after he fell off the train?
The Hydra experimentation on Barnes causes him to survive his fall, and he is recaptured by the Hydra wing of the Soviet Union, where he is tortured and brainwashed by Arnim Zola and turned into the Winter Soldier, a mind-controlled super soldier with a metal prosthetic arm.
