Just because Michael's words were self-serving, doesn't mean that he was wrong. In the words of General Smedley Butler, a highly decorated US officer, who was notable for fighting against corruption:

"I spent 33 years and four months in active military service and during that period I spent most of my time as a high class thug for Big Business, for Wall Street and the bankers. In short, I was a racketeer, a gangster for capitalism... Looking back on it, I might have given Al Capone a few hints. The best he could do was to operate his racket in three districts. I operated on three continents."

I don't want to downplay Michael's evilness, but objectively speaking, 20-ieth century was fool of people committing the most appalling crimes for variety of reasons and getting away with it more often than we'd like to admit.



To be fair, that was the situation he was in after he entered the game.

I also don't think that Michael confused his real and crime family, much.
The book strongly hinted that if Michael lost control of the crime family, then his extended real family would have been in dire straits.
Sonny didn't leave an estate, so his widow and kids were supported by the Corleones.
And prior to their marriage in the novel Michael told Kay that it would take some tricky re-structuring for her and their kids to be able to inherit anything should something happen to him.
And of course, one can readily imagine the consequences to Connie and her kids if Corleones fell, given how Carlo treated her as it was.
Not to mention that Tom and Fredo would have been in danger, too.

Now, movies kind of sideline this aspect and generally ignore the third generation apart from Michael's own kids (Vincent doesn't count, being completely out of the left field), which is a pity, IMHO. Godfather being a sprawling family epic and all.