Thanks, David. I figured it had to be something like that when you mentioned Superman in the next sentence of your post above.

Well, since we're talking about the Marvel Universe perhaps once Mephisto turns the clock back on Peter the same happens to the rest of the world and all storylines, including the Captain America assassination, can be explained away.

And, if Peter and Mary Jane never married then could Gwen Stacey still be alive? I was amazed when, shortly before I stopped reading comics several years ago, the Green Goblin came back from the dead after being absent since 1972. Now, that was a storyline that expected a lot from younger readers, knowing the storyline and occurrences from over three decades earlier.