The hot rumor is that the Green Goblin is about to make his MCU debut. While we've all been thinking cosmic for the next major threat to the MCU, Norman Osborn could very well fill that role.
The word on the internet is that the classic villain will appear in Spider-Man: Far From Home. After that, he's rumored to be a featured villain in the Captain Marvel sequel. Some are speculating that Marvel Studios is planning to set up the Dark Reign story arc, which will put a huge spotlight on Spider-Man's arch nemesis.
What does that mean for collectors? It's not like copies of Amazing Spider-Man #14 aren't already silver age grails and having that designation gives it a hefty price tag. Even the low grades are in the triple figures, and they have been for years. Where collectors will see the biggest impact will be on the Green Goblin/Norman Osborn secondary keys especially the modern ones. Here's why.
When people think of Norman, they automatically tie him to the Green Goblin. In his first incarnation in the comics, he terrorized Spider-Man in his silly outfit and is most famous for killing Gwen Stacy in Amazing Spider-Man #121. Of course, we've seen all this before from Norman (and Harry) Osborn between the 2002 Sam Raimi Spider-Man movie and in 2014's the Amazing Spider-Man 2, so Marvel Studios isn't likely to want to rehash that story.
The other part of the equation is that Marvel appears to be setting up several arcs from the modern age. That's why I don't see the Green Goblin coming to the MCU, but simply Norman Osborn. Maybe simple isn't the word because adding Norman to the cinematic universe could be an absolute game changer.
When Norman was resurrected in the 1990s, it was revealed that he survived the events of ASM #122. Since then, he headed up the Thunder Bolts and took command of the SHIELD replacement, HAMMER. That gave us the comic incarnation of the Iron Patriot, which led to Dark Reign.
After the events of Avengers: Endgame, the stage has been set for Norman to take control of the Iron Man armory and instead of appearing as the Green Goblin, he can be on screen as Iron Patriot. Don't forget that the Iron Patriot armor was already established in Iron Man 3 (maybe the only good thing to come out of that dreadful movie).
Let's say that the MCU Norman takes over either HAMMER or SHIELD and transitions into Iron Patriot. That could easily lead to a movie version of Dark Reign and eventually the Siege story arc, which saw the Dark Avengers destroy Asgard. Considering that Endgame gave us a terrestrial Asgard for the remnants of Thor's people, (and, yes, Asgard is not a place; it's a people), it stands to reason that a team of villains led by the Iron Patriot would wage war on it.
You see, bringing Norman Osborn into the MCU gives Kevin Feige and his super-friends a fresh batch of ideas to play with. If they follow the blueprint from the comics, Norman could very easily become the MCU's next Thanos.