You don't need to base it on actual granular skills, though.
In Shadowdark, characters get advantage on anything they might reasonably be able to do, based their background, class or ancestry. Those three axes provide plenty of differentiation among fighters and no one needs to be worrying about how many points they put in Climb and if they can afford to put any points into Heraldry.
D&D has had backgrounds since at least the 1E DMG but never really leveraged them well until 5E. Something like the Shadowdark system could have been implemented long ago without adding significant complexity to the game -- certainly less than non-weapon proficiencies and later skills added.