Everyone complaining about why a kingdom made instruments their lifeline surrounded by sea when devil fruit users who can't swim exist by the factory load and still become pirates sailing the same seas
The idea that a kingdom becomes dependent on a single trade is survival. many countries today are dependent on a single export. And it's not the fact that the instruments corrode easily by water it's the fact they ALL corrode at roughly the same time old and new. The fog is unnatural to their kingdom and wholly unexpected, even the people get sick from it
Also from econ pov having an expected lifetime of instruments isnt that bad cuz that keeps customers coming back after their old ones break or rust. Instruments are as only good as the owner keeps them and some go out of style too. Its just business