IANA historian, but do read contemporary scholarly history. Chris Wickham whom everyone seems to respect thinks that population in most regions of the Western

IANA historian, but do read contemporary scholarly history. Chris Wickham whom everyone seems to respect thinks that population in most regions of the Western Empire fell by 50% or more after 300 AD. Setting aside arguments about what the "fall of an empire" means, a 50% decline in population is much more serious than administrative devolution. I'm sure that anyone in that period who could see a large enough span of time would have felt something major was lost.