[Polydamas]

The problem there is that there really is a large body of general knowledge which one learns in a job like "infantryman" and which is separate from the skills of most outdoorsmen or marksmen or electronics repairmen. It does increase with time and skill, so it can't just be a perk (and a perk takes up as much space on the character sheet as a skill).

Most GMs and players won't know exactly what things would be included for a given job and culture, so it makes sense to use one skill to include them all. But I think that overlapping skills is a good thing, as long as one skill does not include all of another.