I agree, at least to a certain extent. As a matter of fact, I doubt Michael was completely free to choose not to get involved in his father's business and succeed him as a Don. I tend to believe he was rather compelled to crime, not just for crime's sake or lust for power (not at the beginning, at least), but basically because he was the only one who could take revenge over his father's hit. He felt he ought to be loyal to his father. As strange as it may sound, being loyal to his father (hence killing Sollozzo and McClusky with his own hands ) was the only "moral" thing to do, the only acceptable option, under the given circumstances. If he hadn't do it, he would have been a traitor of his own blood. He couldn't have lived with such a shame on him. Of course he could have refused to do it, but he didn't. His "sicilianity" obliged him. Then it was too late to go back. His fate was in fact waiting for him. He had thought he could escape, but he was wrong, he couldn't. His identity was in his blood. At this point, the dark side prevailed.