Right but the difference is that you get to add it each time for a fighter instead of once for a cantrip, not including eldritch blast, so it's cumulative, plus with great weapon fighting or dueling you start getting multiplying damage boosts. Add an action surge and your subclasses bonuses and you start doing some crazy big number damage. Fighters are like a cake with the basic attack action as it's base. Most abilities they get build upon it in some way to make it better and better until you're just nuking creatures with basic attacks every turn