Apocalypse is more specifically a X-Men baddie though. That’s not to say he couldn’t fulfill the Thanos role, but he’s a little too tied to Mutants and their history as a species. Whereas Galactus, while he debuted in F4, is more commonly used as a villain for the wider Marvel Universe - at least from what I’ve observed.
"I love mankind...it's people I can't stand!!"
- Charles Schultz.
The way I see it, in terms of a meta-story, i.e. a big throughline that you can group multiple movies around and make into a 2-Part epic extravaganza, there's basically only a handful of stories and handful of villains who can spin it:
-- THE INFINITY GAUNTLET and Thanos.
-- AGE OF APOCALYPSE, with Apocalypse.
-- SECRET WARS (1984 and 2015), with Doctor Doom.
Characters like Galactus for instance are big villains but they would never work the same way Thanos did because the character doesn't have all that depth. Either Galactus eats Earth or swallows the universe or he doesn't. There's no way you can tease out a status-quo with Galactus eating everything and surviving at the end of time only to die and restore the universe again.
Whereas Age of Apocaylpse offers you a literal status-quo where Apocalypse rules the earth. Secret Wars has Doctor Doom becoming God of the Multiverse (and based on LOKI's first episode on Disney+, it seems like that's where the next meta-story will go). All stories also sold big in the comics and were big event storylines.
Whereas other villains generally don't offer the same breadth and same scope.
I mean more how Galactus is a force of cosmic nature and not necessarily a guy who schemes with far-reaching plans. MCU Thanos still had that.
At some point characters run of new things to do, tbh. I think Galactus can work as a major threat, but not in the same way Thanos does, outside of having all the heroes join forces
The Avengers don't fit against Galactus either.
Besides, not everything in the Marvel Universe has to, or will always, center around the Avengers.
In the case of the MCU, they're in the process of making it more and more like the Marvel Universe and gradually undoing or overturning some early adaptation choices they made (like Wanda and Pietro getting powers from the Infinity Stones).
Just read Age of Apocalypse, not much I can say aside from that. That was the biggest story Apocalypse had in comics where he took over the world. It's not a great comic, nor is it the best written version of Apocalypse (for that read Hickman's X-Men and the X-team crossover, X OF SWORDS) but it's worth doing as a movie.I suppose it could be modified, but can Apocalypse withstand all those heroes fighting him?
Likewise, being an Ancient Egyptian, Apocalypse has connections to Rama-Tut or Kang the Conqueror, so there's also that.
I never said everything had to center around the Avengers. My point is AoA doesn't necessarily work as a multi-franchise story arc like the Infinity Gem saga does
I read some of AoA a while ago. I think AoA could work in live action, but apocalyspe needs proper build up. Maybe he'll keep his connection to Kang in the MCU
If you look at the comics version of the Infinity Stones saga, it started in the pages of Captain Marvel comics, Silver Surfer comics, and the Infinity Gauntlet event has Adam Warlock as the main hero fighting against Thanos. The Avengers, the FF, and the X-Men are essentially side-shows in the original INFINITY GAUNTLET series.
AGE OF APOCALYPSE includes on the onset a much wider pool of characters and a bigger scale than IG did.