Steve takes things like personal responsibility and respect seriously. Tony's got people he pays to take care of that kind of thing, and anyway, he's pretty sure that he's going to die of some exotic disease in his workshop, because Dummy's still a little spotty about what is 'clean' enough to put on an open wound. The rest of the Avengers are in this for personal gain, except for Clint, he just enjoys being a dick. And some things shouldn't be a chore.

“He’s not telling us everything,” Fury reached out and shut the projection off, “I’m not comfortable with this.” Coulson didn’t respond, didn’t need to. “Let Rogers know I want Barton watched; he doesn’t go anywhere alone until we understand exactly what’s going on. I’m not losing him to some egotistical mind-f***ing blade-dancer who has mentor issues and wants to take it out on our asset.” Phil nodded efficiently. He couldn’t agree more.

"When Tony Stark was seventeen years old, he built his first AI. On that day, he ceased to be his father's creation, and became a creating force in his own right. That one act likely saved his life, and not always in the most obvious ways."