Englehart's Nomad story (see also Gruenwald's The Captain, see also Civil War, see also Roger Stern's Cap #250).
Cap has turned from the government on a number of occasions. Contrary to popular belief the Nomad story, although the first of it's kind, was far from the ONLY time Steve has fallen away from the government. As such, when Steve went back to being Cap, after the numerous times he had one of these aforementioned 'falling outs', he would come to the same epiphany, over and over, so much so that this epiphany has became quintessential to the character. And it marks the very reason Steve has lasted as a character, never falling out of fashion, because this realization that Steve has after Nomad, after The Captain, after serving as Top Cop makes Steve transformative.
I do not wear the flag in support of the government, I wear the flag in support of the dream.
The Nomad arc doesn't end until Cap picks up the shield again. And for some variation of the aforementioned reason, i.e. I Serve The Ideal Not the Reality. What that 'ideal' is can change with the times.
Second unfinished arc: The Accords (SHRA)
They are still present. In fact, despite how busy Infinity War was, the writers went out of their way to include a Ross cameo to remind us of them. In the comics, when Steve came back from being 'not dead' (he didn't actually die, he was traveling through time) he defeated Norman Osborn following the Secret Invasion/Dark Reign/Siege storylines. And when that happened he was made Commander Rogers - America's Top Cop, overseer of SHIELD and the Avengers - and overturned the SHRA and pardoned everyone who was on his side during Civil War.
So, there you go, Nomad/The Captain/Civil War and the Accords are both Steve's to tie up. Not allowing Steve to tie those up would be bad writing, and a punch in the face to fans of the character.