Actually, The Godfather Trilogy is a very accurate portrait of what the Cosa Nostra looks like the the executive level. However, it is slightly over-refined, and elegant in those three films than in most other films (or in real), but in Part III we see what a real mob boss operates like (sort of, Luccese later in the film, and the Commission meeting in Atlanta).
If you've read the real life stories of Paul Vario, Tommy DeSimmone, Jimmy Burke and Henry Hill (All real life counterparts of the film characters), then you'll probably know that they did in fact hijack airports and steel from truck drivers. I.E, they were soldiers in the film, and they were soldiers in real life. Paulie was a capo for the Luccese family. You cannot compare this film, to the Godfather. However, you can rate its quality and accuracy, and on both levels, the films are top notch.
Scarface, however, has nothing to do with either the Mafia or those films, and is completely independent of the genre. It simply shows the upheval of a low level cuban hood to the high level of drug kingpin before his inevitable downfall due to drug addiction and arrogance.
Your points are well taken, however.