Maybe he came to grips with the idea that he couldn’t alter elements of his own history that would prevent him from traveling back in time, so he made peace with the idea that he would eventually save Bucky circa 2014 and spent the intervening years helping the world by fighting secret battles that we never knew about. Like that time he stopped Dr. Doom from taking over the Western Hemisphere in 1967 or the time he prevented Earth from being consumed by Galactus in 1982. Wait, you never heard of those things? Of course not, that’s because he was really good at what he was doing.
