Warning: This post contains MAJOR SPOILERS for Avengers: Endgame.
Where did Old Steve come from?
If we're going off the time travel logic presented to us in Endgame, then Steve went back to 1970, when he and Tony traveled to in an effort to get the Tesseract prior to when Loki ran away with it. Also to acquire more Pym particles to continue their time traveling efforts. By going back to that time, as well as the times and places visited by the other Avengers, Steve would have effectively closed the time loops the Avengers created. But instead of jumping back to the present, he decided instead to go back in time – most likely to the 1950s, a.k.a. after the events of ABC's Agent Carter – to live out the rest of his days with his long-lost love. That means the elderly Steve we see at the end of Endgame is actually present-day Steve, who presumably lived in hiding and away from the major events of the Avengers films. He went back in time and stayed there, aged normally, and waited until the exact moment he could pass along his shield to Sam Wilson.Who is his wife?
Old Steve Rogers is wearing a visible wedding ring when Sam speaks to him. Sam asks who the lucky lady is, and Steve respectfully refuses to talk about it. We can assume, given the scene we see next, that the woman he married was Peggy. That lends a whole new perspective to the scenes we see in films like The Winter Solider and Avengers: Age of Ultron. Knowing that Steve and Peggy were married all along makes their "reunion" in The Winter Soldier more layered. Peggy is saying goodbye to the young Cap – "it's been so long" – while her husband, the aged Cap, is somewhere offscreen. But this does present another possible wrinkle in the timeline...What about Peggy's husband?
In The Winter Soldier, we see Peggy in the WWII museum talking about her husband, a man who served as the member of a battalion over one thousand soldiers and was rescued by Captain America. Fans have wondered since Agent Carter's cancellation who this mystery man might be. It was never answered on that show, or in the films, but Endgame presents a few possibilities. The first is that Peggy married some random veteran we've never met, and the second is that this whole interview was a smokescreen to hide her secret marriage to Steve Rogers. The latter seems more likely. Especially when you re-watch her scene in The Winter Soldier. On her deathbed, Peggy talks to a young Cap, and we see photographs of her children on her bedside table. Conveniently, there are no pictures of her husband, meaning he could be anyone. It's likely, then, that the husband Peggy refers to in the film is actually Steve, and she never mentions their peculiar situation to his younger self because she knows it would compromise the series of events that led them to one another. Instead, she acts as if she hasn't seen him in decades.What will Steve do next?
We see Steve pass the torch (shield, really) to Sam at the end of Endgame. We don't, however, get a definitive "death scene." Even so, it seems pretty obvious that this is Chris Evans' last film in the MCU. He's hinted as much for a long time, and ending the film on his dance with Peggy feels pretty finite. The best way to look at Avengers: Endgame is as his swan song. He may not have literally died, but those final frames are his spiritual "death." Knowing that the main events of the Avengers films end on Cap and Peggy's final dance makes this entire journey feel worth it, and means it's come almost totally full circle. Who can be mad at that?Images: Disney, Marvel