To what extent were Mozart and Salieri's tradgedies caused by themselves?

In Peter Shaffer's Amadeus, Mozart
has the God-given genius but none of the emotional or political savvy to be successful.
 A former child prodigy, he behaves, well, like a child still.  He makes crude jokes,
mocks the court, flirts with all the ladies, and pouts when not given his way.  Mainly,
though, he is haunted by his father.  He knows that he owes much of his talents to his
father, but he seems never to live up to his unwieldy expectations.  Whereas his father
and Salieri measure success by public and material show, Mozart measures it inwardly and
artistically--the way God intends.  In this way, Mozart works himself to death, trying
to please his father instead of his heavenly father or
himself.

Salieri is Mozart's foil in every way.  He has
none of the talent, but all of the political cunning.  An overachiever, Salieri suffers
from morbid jealousy, a need for spiritual revenge, and an intense inferiority complex.
 He curses God for giving Mozart all of the talent; more, he curses Mozart for taking
all his talent for granted.  A two-faced hypocrite, Salieri befriends Mozart, only to
destroy him.  He uses women and Mozart's memory of his father to drive the prodigy to
bankruptcy, near madness, and death.