Heretic of The Seventh Circle
This isn't really true, though. The difference in fighting ability between a fighter of any kind and a bladesinger is pretty big, and firmly in favor of the fighter.The thing to keep firmly in mind here is that Bladesinger is a far better fighter than Eldritch Knight is a caster, and Bladesinger is a fully-functional caster too.
Meanwhile, there are two levels in a standard campaign wherein the fighter is choosing between normal attacks and a SCAG cantrip attack, those being 5 and 6. Before that, SCAG cantrips are better unless the fighter is a duel wielder, and after that the fighter is usually best off using a cantrip as an action and then attacking.
But the figther has a fighting style, action surge, and second wind, all of which increase the efficacy of the fighter's weapon-based combat.
The Bladesinger gains no extra HP, no self healing, and must cast leveled spells in order to boost their combat ability more, many of which are concentration and/or take an action to cast.