IU there simply aren’t any positions available on the chain as it were. That said, Harry is hardly without prestige-he gets to captain the ship when Janeway is off duty, the night shift, he goes to senior staff meetings, and is apparently the highest ranking junior officer(that seems to be what Warhead implies). In every timeline where voyager returns, Harry advances through the ranks rapidly. As he clearly has more experience than any ensign would.
I've got eight, count 'em
eight Starfleet officers who say that
doesn't matter!
1. Geordi LaForge - Promoted to Lieutenant Commander, remained chief engineer of Enterprise.
2. Deanna Troi - Promoted to Commander, remained ship's counselor.
3. Worf - Promoted to Lt. Commander, remained security chief on Enterprise (moved to DS9 a year later).
4. Benjamin Sisko - Promoted to Captain, remained DS9's commanding officer.
5. Jadzia Dax - Promoted to Lt. Commander, remained DS9's science officer.
6. Julian Bashir - Promoted to senior lieutenant, remained DS9's doctor.
7. Tuvok - Promoted to Lt Commander, remained Voyager's security chief.
8. Tom Paris - Reduced to Ensign and promoted to Lieutenant, remained Voyager's helmsman and part time Sickbay assistant throughout.
Harry could have, and should have, been #9 on the list.
There is no legitimate excuse for Harry's seven years as an ensign. None.