But you can't confuse IRL genetics with D&D genetics, they're not the same thing. Dwarves have no bonus to Intelligence not because they're dumb, but because they're not predisposed to use arcane magic and that's the stat that governs arcane magic. If you want to have races with stats adjustments there's no way to go around this in D&D because the only solution is to decouple parameters like "magical attack", "physical attack, "magical defense", and "physical defense" from the six standard abilities, and that's something that will never happen because the six standard abilities probably are the only sacred thing in this game. You can no longer have D&D without Str, Dex, Con, Int, Wis, Cha, and, consequently, their meanings.
Fantasy worlds have stronger ways to influence races than mere genetics. Gods are real and influence their people, legends and myths are real, magic is a tangible thing. Obviously it al depends on the specific setting, but you can't forget that this is a product that needs to be sold and in the minds of most players certain mental associations are absolutely fundamental to link D&D to a certain type of narrative, so you can't expect WotC to ignore those associations.