Just for purposes of discussion,let's assume that Vito decides to end the Corleone's involvement in any criminal businesses in order to get Mike elected to a major political position.
Let us also assume that Sonny isn't killed.

My question is,what happens to Sonny and Fredo?
How do they make a living?

I can only guess that Vito,Mike.and Tom could manage to set up some legitimate businesses for them,so that they could have a legal income.
What about the rest of the Family associates?
We didn't really see them in the movies,but the Corleones must have had quite a few members.
It's quite possible that they could be absorbed into one of the other Families.,and continue in the rackets.

Any thoughts?