The time when
that's not strictly true is when machines came with
optional EPROMs...
It's also not the case with different versions of those EPROMs.
Exactly the flame that burns in my black heart, all of the neat roms for my
HX20, Rev C eproms for my video card, ROM 3 roms for my IIgs, etc.
Three parallel efforts, preserve the data, locate and preserve the parts,
and making any part a persons heart (black or otherwise) wants available at
a reasonable price.