The new mobsters values have changed. They care about the mob until they caught doing something and then they turn on it.

If they had to spend any certain time in prison they would do anything to save their own ass. The mafia code of silence is not taken seriously anymore.

They want the fame and fortune but to go away to prison for 15-20 years is not worth it to them. So once they get caught they turn into a rat.

The old school mobsters are proud to know that they have served their time honoring the promise they kept when they were made. Its an honor to them to have spent years in prison over something they feel so strongly about. Plus remember, the Witness protection program caused many mobsters to turn rats. It wasn't created until 1970. So what do they do? The feds offer them a new name, a new house, protection for them and their family, and a new job if they give up their own people when they are caught with a crime that will send them away for years and years.

The old school mobsters in the 40's, 50's, and 60's never had the opportunity of the Witness protection program, so they kept their mouths shut and did their sentence.

Times are different now. Its the same thing as the guy in Charlie and the Chocolate factory who offers Charlie a better life to get inside information about Willy Wonka.