The concluding shot is a deserving tribute-a frail, dust-beaten image of the old Michael Corleone stooped in a chair, open to the sun, slowly falls unto the earth lifeless; him a moral idealist, son, brother, lover, father, and above all Don corleone, breathes his last - lonely and alone, resigned and trodden like a common man. He has lost his father, brothers, wives, friends, mother , daughter and the grand empire he constructed, in fact everything that he ever valued. He has no more to offer, accept, refuse or bargain. His entire life has amounted to neither individual glory nor personal love that could be cherished. He is not a successful hero , not even a failed martyr. Yet he has changed the world around him irrevocably as such and given every possible chance he would continue to do the same. And In that-- he has transcended himself, history, and humanity thus transforming himself into an idea, into an abstraction , into Ubermensch.
As Uber replies to a comment, we all have our own Nietzsche. It is the parallels that are interesting.