Postwar, ...
The 5" was true dual purpose with more range,
Different guns for different jobs.
I agree with all of the above but I think it mealy shows that the numbers are to vague to tell us anything definitively without closer comparisons of each categories and by year to get a reasonable idea of what to go with.The Bofors, though, was useless as DP gun.
Anyway since this is a BB thread I think secondary/tertiary systems like DP/AA guns can be swapped or changed far later in the design than the main guns so not sure it matters much. They would simply use the best that was available in 38-39.