I think that in spite of his words to Kay and his entry into the casino business,Michael had no intention of going legit after the killing of Sollozzo and McCluskey. At first,granted,he was a naive innocent as far as the reality of the Family business.
As things progressed,he transformed into the ruthless,lowlife Mob Boss,and I believed he enjoyed every minute of the power and fear that he generated.
He wouldn't have put it that way, but there's no doubt that he wanted power, and liked exercising it. Fear was part of exercising power.
After Sonny and Appolonia got killed,was the massacre of the Five Family heads really necessary? I mean,I know Barzini was going to make a move,but wouldn't it have been enough to just take out Tessio and Barz? The other Family Bosses were not a threat to Michael,except in his head.They could care less about Barzini,and just wanted to get back to business.
In the novel he kills only Tatt and Barz, sparing the others, probably for the reason you cited. I think FFC had all of them killed--and all the killings on the same day--for dramatic effect.
Same with Fredo and Hyman Roth. Both were in effect neutralized,but Mike had to go the extra mile and kill them out of some warped sense of honor.
I disagree with you here. Roth showed himself to be incredibly resourceful. As long as he was alive, he was a threat to Michael. As for Fredo: we saw the depths of his hatred and resentment for Michael in the boathouse scene. We saw that he was willing to betray his brother to get what he thought was his. How could Michael ever trust him again?
Bottom line,Mike loved being a gangster,and despite the opportunities he had to really get out and go legit,he took none.
Yes, he had alternative choices at every stage of his descent into the Mafia life, and he invariably chose to be in the life.
