Quote:Storytellers are professional tricksters & cheaters (to paraphrase American Gods and Anansi Boys). So, yes, I totally agree that the creators of the movie bended their own rules.
I did come upon one possible proposed explanation - that Steve Rogers kept some Pym formula and the time device for returning to 2023 after Peggy died. I do have to wonder though that since we have all these branching timelines now, how would it be determined which one Steve landed in if we were to accept this explanation.
Well Steve had enough Pym formula for the return trip, he just used it to go back to 1945 instead. Even if he didn't, he could steal more from 1970.