What's the Detriment of a Great Writer?

Schopenhawer's thesis throughout these essays is that genius is real. He seems the real detriment in those cases is often the tendency to over simplify and extract out of the work sort of effect of the author. Of course, you can look at marlow and shakespeare and see similarities. But then, there are important senses in which sh Shakespeare is pre eminently a not marlow, right?