When The Godfather was written, it was supposed to be a reflection on the way of Mafia life. However, after it came out, and even moreso with the movie, I think that the Mafia has become more of a reflection on The Godfather. Or at least the way the media portrays it. And as a result of that, we have come to expect that established "norm", and perhaps we become disappointed when it doesn't live up to those expectations. Thoughts?

Nice observation. I agree.

Puzo's view of the Mafia, as expressed in the book, may have been reasonably accurate up to the time of the novel's ending (ca. 1955). But the Mafia in the book looks nothing like today's Mafia, or even the Mafia ca. 1970. The only "resemblance" is Vito's prediction that drugs would be the ruination of the Mafia.
The movie was (probably still is) wildly popular among real-life Mafiosi. But just try to find someone with Vito Corleone's character, much less Michael Corleone's brains, among them. :p

Good post LCN!