While I do find Christopher's opinion valid here, I have to join the chorus saying that they would love to see a period piece.
I'm not against a period piece in principle -- the MCU's done some good ones like
Captain America, Agent Carter, and
Captain Marvel -- but I just don't see what there is about the FF in particular that makes people want to associate them with the '60s. Yeah, they began in the '60s, but so did Spider-Man, Iron Man, Thor, the Hulk, Daredevil, the X-Men, Black Panther, Ant-Man & the Wasp, Nick Fury, Dr. Strange, Black Widow, Hawkeye, etc. And of all of them, the FF are the ones most associated with being futuristic and on the vanguard of progress. So where does this desire to see them as retro characters come from? Is it because
The Incredibles was a riff on the FF and was set in the '60s? Or am I inverting the cause and effect there?
The 60s are a blank slate as far as MCU history is concerned and it would be nice to get a look at that era. And just because the movie starts in the '60s doesn't mean that's where it has to end. I recall in Iron Man 2, the recording of Howard Stark saying that he was limited by the technology of his time. I can see Reed Richards in the 60s feeling similar frustrations and then the team winds up in the present day somehow, and Reed gets a look at the technology that exists in MCU 2024 and says, "now this is more like it".
I just don't find that credible. It would take him decades of study just to catch up with the advances in theory and discovery. A lot of his assumptions would probably be too ingrained to unlearn. Granted, the movie could just ignore plausibility and say he was enough of a supergenius to catch up, but that wouldn't pass the smell test for me. Even a genius is a product of their time.
And we already have plenty of modern day scientists in the MCU, with Tony Stark (RIP), Hank Pym, Shuri, and now Riri Williams, so setting the FF in the '60s would also be a nice way to make Reed RIchards stand out from them.
But Tony is gone, and the character who was being set up as his heir apparent, T'Challa, is also gone, leaving a void. As I said, Tony's role in the MCU was basically the FF's role in the comics, so I could see them filling that void. It's not just about scientific smarts, it's about the level of fame, respectability, and cultural influence. The FF are an institution in the comics, the way Stark Industries is in the MCU.