Str or Dex are kind of "soft" requirements.
let's say you have 6th level wizard and 5th level fighter, both use a 1Handed weapon, 1d10 base damage, STR based.
Fighter has 18 STR, wizard has 12(a lot for an average wizard, but wizard want's to be somewhat competent in non magic combat), but how competent is a wizard really.
Let's use AC17(good number for to challenge 5th level characters, but not too high to see hits connect rarely).
Fighter has +7 attack, fighting style for damage of 1d10+6 and two attack.
Wizard has +4 attack, damage 1d10+1 and only one attack.
Fighter has DPR of 12.65, Wizard has DPR of 2.6
Almost 5 times lower.
Even if we give wizard a +3 weapon and fighter deals only half damage as target has resistance to non-magic weapons, fighter will do slightly more damage even then.
Wizard would have to have STR a lot higher than fighter's to even get close to having same damage(if using same weapons and not a caricature of a situation described above).
