...what you have to remember with Tony, and this got pointed out somewhere while I was browsing, is that he's had PTSD since Iron Man One and the cave, and then the Battle of New York happened. The PTSD got compounded, he tried therapy with Bruce who kept falling asleep on him (as it's not his field, the psychology thing), but no word on weather or not he's had any actual therapy with an actual shrink. And because he was letting fear (and the vision of everybody dying, thank you Wanda) drive him, Ultron happened and he couldn't or wouldn't accept total blame for it... to the point of causing Civil War to happen, because he was impatient and kind of a moron and again letting the underiding tension drive him after a woman laid the total blame at his feet (or on his chest) at the start of CACW... which brings us to this question of yours, with the cause of growth and progress. (And I blame the lack of growth and progress at the feet of the script-writers. Gah.) That's a hard one, actually, because I'm looking at this question thru a filter shaded by reading a lot of fic where Tony was made out to be the savior and Steve the villain (and then I had to stop looking at those... seriously) and several viewings of various meta... but... death changes people, both good and bad. The catalyst for Tony to finally make that mental jump toward actually dealing with the problems instead of making the problems bigger ones? The thing that just happened to him on Titan, without actually saying what it was and is, because I'd have to spoiler-blackout myself. He's been worried this whole time that everyone was going to die if he did nothing, that he needed to "do more", that he needed to protect, and in the process of trying to hold on by his fingernails and make everything better... CACW happened. Siberia happened. Half his team ended up fugitives when he was being an idiot and not asking the computer in his suit if there was something fishy about the Doctor (Zemo) that managed to infiltrate the TaskForce building in Berlin. I hope that made sense for you, brodiew.