system
Given the following post, respond as if you're commenting on Reddit:
human
[MCU] What if Tony Stark had never become Iron Man?

How would the MCU change?
gpt
Tony is captured by the Ten Rings but never builds the Mark 1 suit to escape from the cave.  He either submits to his captors' demands and builds a Jericho, or he adamantly refuses.  Either way, Tony Stark is killed.  

Obadiah Stane takes over Stark Industries as its chairman and CEO.  Under his control, Stark Industries expands its weapons development program, and openly sells to organizations such as the Ten Rings. Without Tony, however, the development of new and innovative weapons and technologies grinds to a halt.  This allows competing companies such as Hammer Industries and AIM to catch up with and overtake Stark Industries.  With Stark Industries leading the way in selling to terrorists and other sketchy organizations, other companies begin to follow suit, leading to widespread chaos and instability all over the world.  

Such worldwide instability is exactly what Armin Zola and Hydra were aiming to accomplish, so they launch Project Insight ahead of schedule.  Because SHIELD hadn't developed helicarriers yet, Project Insight instead involves Zola's algorithm identifying potential threats, and then assassins such as Clint Barton, Brock Rumlow, and the six Winter Soldiers are dispatched to eliminate the target.  On one such mission, Clint is sent to remove a rival agent named Natasha Romanov, but instead of killing her he decides to spare her, and recruits her into SHIELD.  For his disobedience, both Barton and Romanov are killed by Bucky Barnes, on Zola's orders.  Hereafter, to avoid other such incidents, only fully controllable agents such as the Winter Solders are used for Project Insight assassinations. Other victims include Nick Fury, Phil Coulson, Erik Selvig, Pepper Potts, Maria Hill, Sam Wilson, Hank Pym, and countless others.  

Bruce Banner, hiding out in Brazil after his gamma radiation accident, is discovered after some of his blood falls into a drink. Events eventually occur until the Hulk has his battle in Harlem against the Abomination. Afterwards, Blonksy is recruited into the Avengers Initiative, while Banner goes into hiding.  Eventually, Banner is tracked down by the Winter Soldiers, and he is killed while in human form.  

Thor is banished to Earth for his recklessness nearly leading to war against the Frost Giants. Due to Erik Selvig's death, Thor never meets Jane Foster, and he is captured by SHIELD when he tries to retrieve Mjolnir. Despite his many attempts at escape, he is eventually interned by SHIELD in a maximum security facility.  Without his hammer or his powers, he has no means of breaking out.  On Asgard, Loki's plan succeeds, and he successfully kills Odin and Laufey, and destroys Jotunheim using the Bifrost.  Many of the Asgardians break away from Loki for his brutality, including Heimdall, Sif, and the Warriors Three.  They travel to Earth together and find Thor, but Loki sends the Destroyer after them.  Thor sacrifices himself against the Destroyer, which once again makes him worthy of Mjolnir. He defeats the Destroyer, but is unable to return to Asgard, due to Heimdall being on Earth and no one else being available or willing to open the Bifrost.  The Asgardians are left stranded on Earth.  

Steve Rogers is discovered in the arctic, still alive.  He is woken up in a SHIELD facility, but breaks out when he realizes the radio's playing a baseball game he'd already attended.  SHIELD recapture Rogers, and he is brought before Zola.  Zola claims that he defected to the Allies after his capture, and has been helping the US and SHIELD ever since.  He shows Rogers the state of the world, one of chaos and unrest, and convinces Rogers that Captain America should do his part to help fight such turmoil.  Zola also shows Rogers that Barnes is also helping SHIELD take out enemy targets.  Rogers finally agrees to help SHIELD by becoming an agent and assassin, albeit rather reluctantly.  

Thanos, noting that the Tesseract is on Earth, strikes a deal with Ronan the Accuser.  Ronan is dispatched to Earth to retrieve the Tesseract for Thanos.  In exchange, Thanos will give Ronan the means to destroy the Nova.  Ronan's massive ship, the Dark Aster, arrives in orbit around Earth.  The Asgardians arrive at the ship to negotiate a deal with Ronan, since Ronan's ship represents their only chance of returning to Asgard.  Ronan explains that he is at Earth to retrieve the Tesseract, and once he has it, he will leave.  If the Asgardians assist him, then he will repay them by taking them to Asgard.  This places him in conflict with the Asgardians, since they believe the Tesseract belongs on Asgard.  They fight, but the Asgardians defeat Ronan.  However, during their superpowered fight, the Dark Aster is knocked out of the sky and crashes in New York.  Ronan and the Asgardians all survive the crash, but they are separated, and Ronan departs on his own to find the Tesseract. Ronan tracks the Tesseract to the facility where it's kept and studied, easily overpowers the SHIELD guards and scientists, and grabs the Tesseract.  However, knowing that there's an Infinity Stone inside, Ronan decides to keep it for himself.  

The Dark Aster crashing to Earth draws SHIELD's attention, and Steve Rogers is dispatched to New York to investigate. He encounters the Asgardians, and a rapport is built between them. Steve brings the Asgardians back to SHIELD, where an attempt is made to detain and/or recruit them.  The Asgardians, naturally, refuse.  They do, however, agree to help SHIELD recover the Tesseract from Ronan, since it now represents their only hope of getting home.  

Ronan returns to his crashed ship and attempts to use the Tesseract to open a portal to Xandar, in order to destroy the Nova.  However, he is interrupted by Rogers and the Asgardians during the process, and in the confusion the Tesseract opens a portal to Thanos's Chitauri army, instead of Xandar.  The Chitauri swarm through.  Rogers, the Asgardians, Blonsky, and other SHIELD agents attempt to stem the tide, but they are unsuccessful.  The World Council, in desperation, fires a nuke at New York.  The device destroys New York, killing Rogers and the others in the process, but it successfully closes the portal due to the massive amount of energy it outputs.  The Tesseract, naturally, is left unscathed.  

Thanos gets out of his chair and travels to Earth to retrieve the Tesseract himself.  There is no one left to oppose him.  Thanos devastates Earth until the Ancient One decides enough is enough, and uses the Eye of Agamotto to turn back time to the point where Tony Stark is captured in Afghanistan.  She uses her astral projection power to plant the idea in his mind that he should build a suit of powered armor to escape.