My take, for what it is worth!
Vito was instrumental, contributed and caused Michael dying “alone and heartbroken, in a decrepit Sicilian villa, attended only by a little dogâ€
The crucial factors [in no particular order!] were -
- The most crucial factor was Vito and Michael's wives
- If Michael's wife Kay was like Vito's wife Carmela, Michael too would have had it all!
When they married Kay knew Michael was Mafia, working for his father unlike Carmela [Vito became Mafia after] - Vito didn't have to contend with his insolent sister, brother's betrayal, wife's abortion etc
- Vito “knew that he could never be “legitimate†in their world, but he hoped for that in Michael: Senator Corleone, Governor Corleone…†thus placing the impossible, unrealistic burden of the “obsession†on Michael “the source of his lifelong frustration:†Thanks! Pop
- It could be argued Michael's “obsession†was Vito's “goal†for Michael
- Vito planned all the dirty work - killing of Carlo Rizzi [for Michael to make his daughter a widow] and Moe Greene, the baptism murders - for Michael to carry out after Vito's death thus leaving a murderous legacy for “I never wanted this for you†son
- Vito could have handed the family business to Clemenza & Tessio and let Michael try to start a new life, away from Mafia, then Michael also could have “died in his garden playing with his grandsonâ€
- Vito “stepped†over Fredo making Michael the Don and Fredo “betrayed†Michael “nearly getting Kay and him killed†which boiled over the downward spiral Kay's that look
- Michael could not “provide fellow immigrants with favors and protection†like Vito as Michael was a “legitimate†businessman
- I believe “in the scene where Michael woos [!] Kay in New Hampshire:†Michael [was genuinely striving] to be considered “legitimate†and not “to be the top Mafia Don in Americaâ€
- Sure thing Michael down the track was never “outâ€:
- Michael “flaunted his enormous wealth with a party for thousands†Vito did similar with a big party for Connie's wedding
- In fairness, no one got Roth’s Havana empire because of the Cuban revolution
- and Times were changing indeed
Nevertheless
- If Michael had not been greedy, burrowing into Roth's empire ie: satisfied with his Nevada gambling business, Roth and Ola would have had no reason to cultivate Fredo to betray Michael and the Tahoe bedroom shooting would not have happened
- Then Kay, part of the same “unholy and evil†hypocrisy, champion self-deceiver that she was, would not have been spooked and unnerved - the trigger to 'abort' their unborn 'son' and may have kept going with “this Sicilian thingâ€
Both Vito and Michael were evil murderous monsters but Vito lived and died 'happy' as could be under the circumstances thanks to his wife, Carmela
Michael racked by sorrow and regrets even before Mary's murder eg: Michael's confession to Cardinal Lamberto
Vito may have coached Michael to Head of the most powerful Mafia family but because of it Michael lost everythingelse
