The Marvel Cinematic Universe has grown a lot in every sense of the word. Its stories have gone from contained origin stories to superhero team-ups and crossovers on a scale not previously seen in cinema. The characters themselves have also grown quite a bit, beginning their arcs as fledgling heroes and progressing over a number of films into a well-rounded characters audiences all over the world over are invested in. With the increase in the scope of stories and its characters becoming more seasoned with every iteration, the MCU is on a trajectory of bigger and better.
How sustainable is this growth for the MCU? Given enough time, Marvel's cinematic offerings could have the depth and longevity of its comics. However, the movie industry is far more reliant on trends, attention spans of audiences and often victim to genre fatigue. In order to circumvent these things, the MCU needs to continue to raise the stakes, excitement and the scope of its narratives.
However, there are several problems with this. Trying to up the ante each time may propel it away from the personal, intimate character stories that run through the MCU and endear audiences to its characters. Chief among these concerns: What if the next villain it set up doesn't live up to the infamy of Thanos?
Let's take a look at the source material, and how its scaling up could or could not be applied to the MCU.
BEYOND INFINITY
From the first glimpses of the outer reaches of space via a portal in Avengers Assemble, the MCU's escalation of its stories has been inevitable. However, with the saga of the Infinity Stones taking the Avengers all over the cosmos -- and even back and forth through time -- how much bigger can things get? Much bigger. The Infinity Gauntlet is just a taste of what is lurking in the Marvel Universe. While incredibly powerful, the artifact and the story surrounding it wasn't on the scale of things that still may come.
With the decimation of the Nova Corps during Thanos' claiming of the Power Stone, he has potentially given the MCU a window to introduce Nova. From here, Marvel Studios could use this cosmic hero as the witness to a famous Marvel cosmic event that threatens all life in the universe, not just fifty percent. The story in question is Annihilation. From a dimension known as the Negative Zone, a bug-like tyrant named Annihilus emerged, with an unfathomably large swarm of all-consuming insects known as his Annihilation Wave.
If the scale of the MCU increases, it needs to be filled with more civilizations to fit the galactic landscape of the comics. The Skrull Empire will need to be rebuilt, the Kree will need to take a more active role and the largest empire, the Shi'ar, might even make an appearance. Universal politics entering the MCU splashes inside films like Guardians of the Galaxy and Captain Marvel, tensions we know can flare across the cosmos.
The heroes could be pulled into incredibly large, star-system spanning conflicts such as War of Kings and could even find themselves facing down the sinister Universal Church of Truth led by Magus.
TIME AND TIME AGAIN
Time travel is something that is awkward to play with in any medium, though Avengers: Endgame managed to find a satisfactory use of it. Although, with the possibility available, would it be used in further Marvel films? With the X-Men on the horizon, it's hard to rule this out. The X-Men and time-based shenanigans go hand-in-hand. Whether they are battling through a dystopian future or bringing younger versions of themselves to the present, mutantkind's history with time travel in the comics could be a vehicle to fully explore the full potential of the time stream.
Currently, the X-Men are undergoing a rebirth under Jonathan Hickman via House of X and Powers of X. These stories span thousands of years worth of potential futures and elements of the X-Men's past. If Hickman's work is to be the canon for the X-Men going forward, then the MCU may replicate elements of this to introduce the X-Men. So, in order to tell a story that maps out the timeline of a group of characters, another trip through the Quantum Realm could be on the horizon.
POWER OVERWHELMING
The MCU has had many foils, culminating in the schemes of the Mad Titan and his attempts to balance the universe. Considering how powerful Thanos was, even without his gauntlet, the Avengers, Guardians and perhaps even the X-Men could struggle against deadlier threats. If we take Annihilus and Annihilation as an example, we have a terrifying prospect for our heroes. Extremely powerful cosmic heroes fell during the Annihilation War, including Quasar. With characters who can bend Quantum energies to their will being snuffed out, the event would be catastrophic for the heroes of the MCU. Out of the current roster, only a few would be able to withstand the onslaught of Annihilus, and that would only be for a short amount of time.
In order to keep up with the escalating power levels of villains, more heroes will need to be introduced. We could yet see veterans of Marvel's space-based stories make appearances, such as the already teased Adam Warlock, the Silver Surfer, Wraith and Gladiator. These heroes could be introduced in further Guardians of the Galaxy films or a Captain Marvel follow up.
Traditionally, however, cosmic stories are often kept separate from Earth-based crossovers as the power levels being used are vastly different. They do blend sometimes, but as shown in stories like Infinity, the Avengers are often underpowered.
The likes of Bucky, Hawkeye and Falcon aren't likely to take on immensely powerful galactic villains such as Galactus or Knull. In the ongoing Absolute Carnage story of the comics universe, though Knull is present as the orchestrator, the narrative has heroes facing off against via Carnage as a proxy. This is because a straight confrontation with these kinds of villains would be disastrous. Marvel needs to be very careful in attempting to strike the perfect balance between overwhelming and plausibly fallible.
This perhaps the MCU's greatest obstacle: capturing the occasion, stakes and gravitas of Thanos and his infinity crusade once again with a fresh adversary.