I would think of it as: as the raw material becomes a greater percentage of the total cost, decreasing total cost becomes harder, both in relative terms (because it’s impossible to halve total cost if raw material is already the majority of the cost) and in absolute terms (because if any decrease in system complexity causes the raw material to be used less efficiently, that will erode savings from the decreased complexity).
In that sense the idiot index acts like pressure making it harder to squeeze costs when they’re low but with very little impact when they’re high.
I would think of it as: as the raw material becomes a greater percentage of the total cost, decreasing total cost becomes harder, both in relative terms (because it’s impossible to halve total cost if raw material is already the majority of the cost) and in absolute terms (because if any decrease in system complexity causes the raw material to be used less efficiently, that will erode savings from the decreased complexity).
In that sense the idiot index acts like pressure making it harder to squeeze costs when they’re low but with very little impact when they’re high.