Tom went to the actors studio. Had a big tv career before he even got into movies.
Oh wait your talking about the character Tom Hagen and not Robert Duvall.
Tom had a wife, mistress and a couple of kids. The Godfather found him homeless in the streets, put him through law school. Yes he had a good life.
It not about what he spent his money on. The point was that he had it if he wanted something he could just buy it.