Was a disassembler ever considered part of the
standard binary objects
toolkit with the assembler, linker, etc. or was that the sort of thing that
was more niche and therefore just kinda cropped up when/if someone decided
to write one?
There was a Vax decompiler around the time of 4.2BSD that was available
from some university (Utah?). It was commonly used to decompile Peter
Langston's empire program so it could be run on a bunch of the other Unix
minicomputers that were available at that time. (E.g., we ran it on
Pyramid's)