Avengers 4 Theory: How Tony Stark And Thanos Are Mirror Images
1. Could Tony Stark Learn From Thanos?
As already hinted, Tony Stark's character development over the past decade is headed in one direction and one direction alone. He's sought increasingly extreme methods to save Earth (and The Avengers) from itself and from external threats and he has the potential to turn into Thanos. Or a Thanos-type figure at least.
Remember that Thanos had to argue his case with his people to kill off half of the planet for their own good: you can see the same instincts and the same indicators in Tony's attempts to influence Captain America to sign the Sokovian Accords. The reasoning is also the same: yes, it might come at a cost in the short-term, but in the long-term it's better than the alternative:
"Gimme a break! I'm doing what has to be done, to save us from something worse."
That is exactly Thanos' reasoning too. And while he's an extreme example (and by no means a morally good character under all of his "integrity" to save the universe), he stands as a morality lesson for Tony.
And if Stark is able to see himself in Thanos - and the indicators are already there that that might be where this is headed - then he might not need to sacrifice himself. His moment of realisation could come soon enough to save him and his and Pepper's dreams of a normal family life together.
Up until now Tony hasn't had enough incentive to hang up his Iron Man costume - as he says to Cap in Civil War he doesn't want to stop - even when he almost lost Pepper during the events of Iron Man 3, but there's a difference here. Tony has always operated on the assumption that he is a fundamentally good man and that everything he does is good if it is a means to a positive end.
Seeing how similar his trajectory is to Thanos' could be the revelation that not only brings him back from the brink of extreme, destructive behaviour, but that also shows him that such ruinous conviction is not a good idea. Thanos might end up being the way he gets out of his Iron Man addiction.