I think Willy defines success in the same terms that most of us do.  He wants to have a job that will provide respect for him and a living for his family.  He wants his children to love and respect him, and his wants his wife to love and support him.

He makes some mistakes in getting to these goals, but they are not that unusual.  His major error is his belief that personality, that being well liked, is central to success in life.  He pumps the boys full of this belief, and it keeps them from solid development (in some ways it reminds me of the recent tendencies to reward young people for everything --- even the last place team gets a trophy).  He never notices that he is growing obsolescent, that the world has changed around him and, in fact, passed him by.

He does a lot of incorrect things, but they are all the results of his desire for what most of us want.