Avengers 4 Theory: How Tony Stark And Thanos Are Mirror Images
3. Doing Whatever It Takes
Obviously, Thanos is willing to wipe out half of existence to rebalance the universe and save it from itself and that would traditionally see him labelled an irredeemable villain, but there is logic to his desire. He knows that even the Infinity Gauntlet cannot save the universe and this is very much a last gambit that MUST be undertaken. And him confirming to Gamora's spectre at the end that the price for his victory was "everything" shows he didn't take the decision lightly.
But Tony Stark has done similarly dramatic things (albeit without the genocidal twist) in his past to make sure the Earth is as safe as possible. He created an Iron Legion, he built Ultron, he signed the Sokovia Accords and ripped apart the Avengers... Every action he's taken - including attempting to goad Bruce Banner into becoming The Hulk - has been precisely designed to one end. To stop the day coming where he stands over the bodies of his fellow heroes and watches the Earth's destruction or dominion.
As Anthony Russo recently confirmed to The Telegraph India, there is desperation to Tony's drive...
“It’s all the heroes. I think he has the most specific connection to Tony because Tony is a futurist, and he has predicted a threat like Thanos. It’s lived in his brain even though he couldn’t name it. Tony is the most desperately driven, down to the core, to react against something like Thanos, although all the heroes will face a threat, no matter who it is or where it comes from. But I think this is intrinsic to Tony’s psychology, and because Tony started it all with Iron Man, he has a special connection to the threat that’s facing him.”
But it isn't just desperation that he has predicted a Thanos-like threat that specifically connects the pair, there is kinship both in their fears and their willingness to give it all to find a solution.
And if you think Tony wouldn't do exactly the same as Thanos if it meant saving most of the universe, you probably haven't been paying attention. That is his curse.