to what extent is macbeths downfall caused by a failure to distinguish between illusion and reality?

Macbeth wants an illusion. The witches merely suggest things he likes to hear. It is Macbeth, with the aid of his aggressive wife, who really creates the illusion of royalty for himself. To keep his illusion alive, he must wade in further to murder and deceit, “I am in blood stepped in so far that should I wade no more, Returning were as tedious as go o'er.” By the end of the play people see Macbeth for what he really is, "feel his title / Hang loose about him, like a giant's robe / Upon a dwarfish thief."