I'm going to take issue with those numbers, partly because a rogue would generally use an off-hand weapon
That doesn't do much for a Rogue because he either loses Vex or loses cunning action and stedy aim. Also he does not add damage to an offhand weapon like a fighter does.
Dual wielding at 5th level is 2.5 DPR more than using a Rapier, which would be 21, still less than a Fighter.
In play in 2024 though a Rogue with a shortsword and Scimitar is actually better not attacking with the Scimitar if he hits with the Shortsword. This way he does not lose the advantage associated with Vex, but it costs 1 DPR because he is using a light weapon.
In 2014 this was a significant advantage for a Rogue, in 2024 it isn't. A Fighter with Vex weapons is going to get advantage from mastery more than a Rogue is going to get it from steady aim. Further they can do higher damage with Vex because they can do not need to save their bonus action, so they can get Vex after every hit on one creature and can also do it from range with higher damage non-finesse weapons.
The only way a Rogue will get a higher percentage of their attacks with advantage than a fighter built for advantage is by using a short bow which has lower DPR. A single Rapier Rogue will almost keep pace with a fighter, but at lower damage.
Steady aim also requires a situation where you don't move. This is not viable in play every turn or even most turns and often you are going to be dealing with cover penalties regularly if using ranged weapons and steady aim.
and partly because you're not actually including chance to hit, which gives Rogue a boost.
No it isn't. Using Topple and Vex a fighter is going to get advantage more than a Rogue (primarily because they are making more attacks). Dual wielding they will get it a lot more than a Rogue because they can dual wield two Vex weapons. Further with Graze a fighter does not even need to hit at all to do damage.
If you want to consider steady aim, and advantage then you also need to consider Vex, Topple or Graze and consider rounds where the Rogue does not qualify for sneak attack and loses that extra 3d6 completely. Considering these kinds of things will make it worse for the Rogue, not better.
They also have a smoother progression than other martials, so looking at when the fighter damage gets its highest spike may also skew the overall impression somewhat.
I am not the one who chose 5th level, there are some levels where a hypothetical Rogue in a whiteroom with no subclass or feats will slightly outdamage a hypothetical fighter, but if we only look at basic class abilities they will be behind at most levels from 1-20. If you add feats and subclass abilities they will be behind at every level except 2 and 3.
Rogues aren't going to be beating berserker barbarians at dealing damage at this level, but they do better than you portray.
I am portraying that they are do less damage than other non-casters, and they do. There is nothing incorrect with that statement.
Even with an optimal 2024 rules build Arcane Trickster gaining a damage boost from Truestrike they are still behind other non-caster classes at most levels.
