system
Given the following post, respond as if you're commenting on Reddit:
human
[MCU] If Loki wasn't meant to escape in the 2012 timeline then what happens to Captain America in the original timeline?

So when Loki escapes in the 2012 timeline with the tesseract, that forces Tony and Steve to go back in time to the 1970's to get the tesseract there instead. But if they had received it in 2012 and immediately returned to 2023, What would have Steve done after the Battle with Thanos? 

Does he still go back in time to Peggy? To me it seems that Steve decided to go back in time once he saw his own picture on her desk and Peggy herself through the window. But would he still go travel back if that moment in the 1970's never happened?
gpt
The misleading thing about the Sacred Timeline is that it is not about what is supposed to happen, it is about what is *not* supposed to happen.  The thing that isn't supposed to happen is the rise of an alternate version of Kang the Conquerer in the far future.

For whatever reason, Loki's individual contributions to the timeline tend to cause events to unfold in a way that allows a new Kang to be born and discover the multiverse.  

Cap can go back in time and live with Peggy if he wants to.  Or he might never get the chance to do that, it's largely irrelevant.