Curate, connect, and discover
So I’m pretty sure almost everyone that watched Avengers Endgame had a problem with Steve’s time travel back to his life with Peggy and then his appearance as an old man sitting on the bench.
Here is my theory on how it worked:
For anyone who has watched the movie Sliding Doors, this will make sense. For anyone who has not, let me try and explain.
So in the movie Sliding Doors, this woman misses a train and then an alternate timeline gets created where she didn’t miss the train. You then proceed to watch these two timelines play out together and at the end, one timeline “ends” (in a way I won’t explain for spoiler reasons) and the two timelines merge into one. (Hopefully this will all make more sense as I continue)
So when Steve travels back in time (Ignoring the issue that Steve wouldn’t leave Bucky) he created a different timeline where he didn’t get frozen and he stayed and grew old with Peggy. And there were essentially two Steve’s at the same time, just in different timelines. So while one Steve was getting frozen, then found again and then becoming a part of the Avengers in the films we know and love, the other Steve was growing old with Peggy.
Then when Steve went back in time in Endgame the two realities would merge so Steve would turn up on the bench old. And because of time travel shit in the movies even before Endgame, there would’ve been an alternate timeline where Steve was growing old with Peggy. And because of the super serum Steve would’ve been able to live to the age of over one hundred.
And similarly, when everyone went back in time to get the Infinity Stones, when they did go back in time they created alternate time lines, BUT when they went forward in time to get back to their present, the alternate timelines got “destroyed” or just ‘sped up’ to merge with their current timeline.
So Steve still would’ve gone through the movies just the same and Steve wouldn’t have been related to Sharon in the ‘original’ time line, aka the time line we were shown by Marvel (which was a big problem of mine).
I hope this makes sense and if you’re still confused about the alternate timelines go watch Sliding Doors and hopefully it will make more sense.
If you have any questions feel free to comment down below or if you find any holes in my theory (but keep in mind it took me 45 minutes with my mums help to come up with this and give me peace, so maybe don’t overthink it)