It seems to me both Vito and Michael were “reluctant Dons” the Donship was, by all accounts, thrust upon both Vito and Michael, their respective "circumstances:"

Vito having lost his Grocery store job because of Fanucci, then Fanucci muscling in, demanding to wet his beak in Vito's [Clemenza and Tessio's] risky, hard earned money - including to put food on the table for his wife Carmela and their kids

Michael because of Vito's [Corleones] need, pride to re-establish the Corleones glory, standing, reputation etc. that they are not weak and crumbling like everyone says "Vito's desire to make the Corleones top Mafia family again"

The tragedy for Michael is, Michael's situation was not dire like Vito's Michael still had the opportunity to try a new life away from Mafia

Vito embraced the Mafia life “I don't apologize that's my life” whereas Michael to Geary “we're both part of the same hypocrisy”

Vito's bonus! an old fashioned traditional wife, Carmela, with her unconditional love and loyalty for Vito
Michael's wife [“and Kay -- well -- Kay was -- well --”] became Michael's horror