I think this was a joke, but I hope no one has ever made any assessment or decision of any sort on the basis of this quip (incidentally, not Einstein's[1]).
This, of course, is not the definition of insanity, nor is it a remotely good proxy. Doing things over and over again -- whether chopping at that tree or going to the gym or working on a difficult problem -- should absolutely yield different results. All actions accumulate, some more than others.