How did Macbeth destroy Scotland?

Macbeth destroys Scotland, first, by killing the country's compassionate and noble king, Duncan. Under Duncan's rule, people were rewarded for their good services, and the country seemed to prosper, even seizing victory in two wars at once. After Macbeth takes over, however, people are made desperate by fear, hunger, and poverty, presumably because Macbeth hoards everything good for himself. The Lord with whom Lennox speaks in Act 3, scene 6, says that, with Malcolm's help, people might once "again / Give to [their] tables meat, sleep to [their] nights, and / Free from [their] feasts and banquets bloody knives, / Do faithful homage, and receive free honors, / All which we pine for now" (3.6.37-41). Therefore, we can understand that Macbeth's rule has devastated Scotland and her people in myriad ways.

Ross says something similar when he speaks with Lady Macbeth in Act 4, scene 2: "cruel are the times when we are traitors / And do not know ourselves; when we hold rumor / From what we fear, yet know not what we fear, / But float upon a wild and violent sea / Each way and move [...]" (4.2.22-26). He says that men are accused of treason and do not even know why, that so many rumors circulate that one knows not what to fear nor what is even true, and that the country feels adrift in every way. This was not so during Duncan's reign, and so Macbeth's corruption, greed, and paranoia appear to have devastated Scotland.