Before anyone jumps on me, sometimes (and this is just what I'm forcing myself to not believe so I can just watch the damn movie) their friendship seems unequal and utilitarian--one-sided if you will. Fans amplify this in their discourse anf fan content. Of course they don't notice and think they're being benevolent by thinking of this utilitarian as an equal respectful relationship.
But imagine if you did almost everything for someone you called a friend. Imagine if this friend vaguely acknowledged you outside of their other friend.
Yes Steve and Bucky do have more history--they grew up together. That's fair to me. But if the writers and fans want to have Steve and Sam's friendship be more believable, less utilitarian then they need to start viewing Sam as his own person. They need to see Sam outside of Steve and, have Steve interact with Sam beyond the scope of his own needs.