Rogue's Sneak Attack is Oddly Limited

its only 2 times a short rest, and that assassin rogue can guarantee a crit once a short rest at level 20. But that is level 20, and giving the rogue a specific damage focused sub class while the fighter does not. At most levels rogues do not have a auto crit option, or a double damage on a failed con save in the first round option etc. At lets say 13th level which is a pretty normal end point rogues are just hitting for 8d6+dex mod with a short sword. So like 33/34 damage on average. A fighter is hitting 3 times for 2d6+5 without feats, so 39ish. But feats help them more, magic weapons help them more.

But fighters and rogues are not the only martials. A barbarian is only hitting twice for 2d6+8 or 30ish though likely with advantage on the attacks. Against a low AC enemy they will likely get 1d10 more on 1 attack so 35ish damage. 

Now heavy weapon mastery exists and as far as I know there is not a rogue equivalent feat so at 13 another 5 damage per hit which does push the barbarian past the rogue.

Monks at 13 will be hitting 5 times for 1d10+5 which I am told is terrible online. optimizers if they can't find a gimmick to push damage to infinity it sucks.   

If youre playing a game based on fantasy and worried that it doesn't sync up with your real life experiance with a life experiance with a long sword or a spear maybe go play with a long sword or a spear? Fire balls are not real, I can't actually find a real Patron from the Fey Wild. They make decissions that allow each class to have niche. Rogues get to turn small easy to hide and sneak up on someone weapons scarly dangerous. Other classes get to utilize larger weapons to fulfil a different fantasy based on different weapons and thats the beauty of the game.

If youre playing a game based on fantasy and worried that it doesn't sync up with your real life experiance with a life experiance with a long sword or a spear maybe go play with a long sword or a spear? Fire balls are not real, I can't actually find a real Patron from the Fey Wild. They make decissions that allow each class to have niche. Rogues get to turn small easy to hide and sneak up on someone weapons scarly dangerous. Other classes get to utilize larger weapons to fulfil a different fantasy based on different weapons and thats the beauty of the game.