if anything we've become less efficient at it. in older days we'd use the bones for stock/arrows/tools etc. we'd use the skin for leathers. sinew for string/rope. fat for fuel and preserving and soap. meat and organ meat for food. nowadays we throw most of it out to waste, organ meat barely gets eaten. leather = murder to some people so its used less and less in clothing taken over by much higher environmental impacting synthetic leather. i've spent a project on waste meats for biofuel and theres so much crap that just doesnt get used anymore.