To start with there is more to combat than damage. The Rogues AC in specific severly limits their combat potential unless you invest in options to get medium armor and if you do this you need hamper stealth or invest in feats to counter it. You also need to invest in strength to overcome the weight, meaning you have to pump both strength and dexterity. Both of these will reduce investment in other areas and make the Rogue weaker in other things "typical" Rogue's excel at. This point aside, at a basic level Rogue SA does not keep up with fighter extra attack in pure damage for a variety of reasons:Rogue Sneak Attack damage keeps up reasonably well with basic Fighter damage of Extra Attack + Fighting Style.
That has never been in dispute.
The Fighter however pays a much higher opportunity cost to do so, and will severely degrade their combat ability, without their non-combat ability ever catching up to the classes that don't pay that opportunity cost.
1. Action surge is 1 entire extra action (with 2 or 3 attacks), nominally 3 times per day. After 17th level it is 3 or 4 extra attacks nominally 6 times a day.
2. Most of the fighter subclasses also bring extra damage to the table, either directly through more damage, more attacks or easier hits. The battlemaster with maneuvers, the champion with crits on a 19 (and aside from the extra damage dice this means a 19 also always hits the target) and additional fighter styles. Samaurai, Rune knight, Echo knight, Cavalier, psi knight all have comparable abilities that are going to substantially boost weapon damage output. The subclasses that don't are the exception for the fighter.
Some Rogue subclasses like Assasin, Phantom and Scout do this too, but their uses are far more conditionally limited or come later in the game.
3. SA is not automatic and requires specific conditions. No Rogue is going to SA every single turn and depending on the type of Rogue you are playing, your environment and the DM it is going to be anywhere between 50% and 90%. The first turn of combat in particular can be difficult to get SA if the Rogue wins initiative and is not hidden or is not an assassin.
You can metagame a Rogue to keep up with a fighter who does not similarly optimize but it takes a specific focus on combat to the detriment of other class abilities and uses.
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