Saw the movie last night...
Those of you who have a problem with the Thor "joke" are having a problem with a decent (for the genre and setting) depiction of how trauma impacts people. It is in part played for the joke (because, apparently, alcoholism is funny to people), but his descent into that and depression are entirely appropriate.
And, to be honest, if you didn't turn from laughing at him to feeling some pity for him... Well, maybe that's on the film, and maybe it is on some of our culture's views on alcoholism and grief.
Mudstrum Ridcully" said:
But I can't quite reconcile how that works for Old Steve Rogers. I mean it's possible there has always been a Steve Rogers that came back at some point to reunite with Agent Carter (clearly after the events of the series), and that's our old Steve Rogers now. But that suggests that travel into the past doesn't always end up with an alternate timeline. But how would the time travel mechanism "know" which option to pick?
No, you got it. The thing we need to realize is... Old Cap is not Cap. At least, not "our" Cap.
When you travel in time, you go to alternate timelines. They establish that the way you get back to your own timeline is *through a portal*. Cap and Iron Man even initiate a jump (to 1970) without a portal, but to return, they use the portal. Without the portal, any time jump you make is to an alternate timeline.
Old Cap did not come through the portal. So, it isn't our Cap. He's a Cap from an alternate timeline.
There's actually a ton of timelines going through much the same thing - each with their own Thanos trying to kill off half the people in its universe. There's a bunch of Avengers jumping through a bunch of alternate timelines trying to do much the same thing. But... *we* are an alternate to someone else. So, Our Cap jumps out, goes to an alternate timeline, and spends a life with alternate Peggy Carter. A *different* Cap jumps from somewhere else into our timeline to deliver the shield.
You only split off a new timeline if you change what you know.
I think you are incorrect. See above.
---
Now, aside from time travel shenanigans -
I like how the one person who manages to get their Infinity Stone by just straight up rational discussion... is the Hulk.