jtthomas is getting to the answer. Little to do with how we define modern science or "today's knowledge" about calorie intake and energy output. Scott's and others' ability to fail is not only b/c of leadership and luck; it was about a superiority complex and not stooping to un-British like conduct.

Success (with Amundsen, Nansen, etc) had more to do with emulating people (who were viewed by most in the "civilized" world as "savages") who survived, even thrived, in extreme arctic regions with generations of knowledge (Inuit) , but had nothing in terms of "today's" knowledge. No doubt these same techniques gained from Arctic regions were used successfully in other places during long-term expeditions to The South.