I think in the 60s Boxing had an identity crises caused by the Russians. There teams use to come west and do well, and we tried to copy to an extent their basics, without looking into the rudiments of why they did so well. Being over 24 with 200 fights and not being sure what was being put in them. The techniques lingered we copied ,there basics are still copied today in Amatuer Seminars. All the fighters you mention are old school taught, sometimes new is not better.