My bad. I forgot about the Thanos as the protagonist. Yet, I think an argument could be made that the consequence of Being would be in Thanos not being able to play the role that he's trying to play, which is Father to all. Which plays into the Relationship Story between him and Gamora (and even Stark -- he wasn't able to be the father figure to Peter that he wanted to be).
As far as the Issues under Doing:
- Thanos is trying to apply the knowledge that he's gained from seeing his home planet destroy itself, while the Avengers are trying to protect Vision, who has a certain kind of Enlightenment because of the Mind Stone. They even mention that because of all of the different "minds" that Vision has, he is constantly learning and gaining insights into things.
Plus, his name came from someone (I think Tony) saying "I had a vision." And it's Vision's insight and enlightened solution that they're all struggling against, and what could have stopped Thanos if everyone has just listened sooner.
- The Avengers are having to pit their skills against Thanos and the Black Order, but are lacking the Experience of working together, while Thanos and the Black Order have plenty of Experience with destroying worlds decimating populations.
To take it a step further, Thanos sees the world and its population as being Non-Accurate, and is striving to make it Accurate (in his own way). He's driven by the fact that his home world serves as proof, and he wants to stop that from happening elsewhere. But he's not making enough progress by attacking one planet at a time.
The thing that really sticks out for me is how Thanos describes what he's working towards -- being able to achieve his goal with the "snap of a finger." He's already been trying to Obtain balance before the story starts. In this story, he's solely focused on how he can do that effectively and efficiently.
And he's doing it in a way that no one else can - he got Eitri to make the gauntlet in order to be able to wield the stones, then made sure that Eitri couldn't make another one by killing all the other dwarves. If he was simply focused on achieving the deaths of half the sentient lifeforms in the galaxy, he could have kept planet-hopping and killing with his army. His end goal isn't the Infinity Stones themselves. It's what he'll be able to Do with them.
Plus, when you think about it, the goal isn't achieved when Thanos gets the last Infinity Stone. Otherwise, that would have been the end of it. But that was the Requirement.
Thor shoving an axe in his chest was Thanos' fall right before the climax. The actual climax - the final driver that brought about the successful conclusion of the story for the protagonist - was when Thanos snapped his finger.
Also, with one of the big themes in the story being Sacrifice, a lot of focus is placed on what you have to do in order to achieve your goals. Whether that's lose something or kill someone,whatever. Sacrifice is something you do. What you sacrificed is something you lose.
So... yeah. Those are my thoughts on it.