I've always thought the notion that the "natural" higher level endgame was domain management was an odd conceit. If you consider James Bond to be a relatively high level spy, for instance, does it make sense that he give up being a field agent and should instead move naturally into M's role? Because that's basically what that endgame paradigm seems to be saying. It doesn't make a lick of sense in other genres, so why is it assumed to be the default in this one? Does a "high level" law enforcement character like John McClane naturally become the head of the FBI? No, he keeps doing what he was doing. He's just a lot better at it than a rookie.
Most fiction, and the real world, are nothing like James Bond and Die Hard movies.
In the actual Ian Fleming novels, it was noted that 00 agents normally have a very brief lifespan in the field, tending to die horribly (the real reason in the novels for Bond's womanizing and drinking is he figures he'll die soon anyway, so live it up). The dozens of adventures of the cinematic Bond is a huge outlier even in the source material.
In the real world, experienced spies (or soldiers, or police officers) tend to move into supervisory positions as they get more experienced.
We take talented combat veterans, and we promote them upstairs and give them higher level commands instead of keeping them on the front lines. The real-world answer is that we reward success with promotions that take people away from "adventuring", whether that's street level law-enforcement, field espionage, or front-line combat. Some people in some professions, like SWAT or Special Forces, or CIA Special Activities Division might last longer in the field with their skill, but getting promoted upstairs is the normal career path.
Historically, a great warrior would be more likely to rise to leadership of an army than to just be a high-powered freelancer. An ace cop or detective would be promoted to Sergeant, then Lieutenant, then Captain. He might be at the station dealing with patrolmen and detectives quite often, but would work very few cases himself and spend most of his time on paperwork.
This idea of the insanely skilled super warrior (or supercop, or superspy) who stays on the frontline for countless adventures is more a mid-to-late 20th century invention than anything rooted in reality (or fiction before the 1960's).