There are several reasons, the first of which is the RICO law and the creation of the Witsec thenthe declared war from 1980 by the FBI, the Police and the DA at 5 Families in New York in particular and other crime families in general.

Very important after the Commission trial, the old and respected bosses were replaced by younger and arrogant bosses but above all greedy,trigger happy and blood thirsty.

An example Anthony DiLapi controlled the Lucchese family's Teamsters union in New York City's Garment District, a bookmaking business and owned part of vending machine company in Brooklyn.He also worked with Thomas Gambino, the son of Carlo Gambino and son-in-law of Tommy Lucchese in extorting business in the Garment district. After being released from prison DiLapi was summoned to a meeting with Anthony Casso, and fled.Casso ordered to whack DiLapi even he is a good erner and he was murdered by Joe D'arco in L.A.;
Casso ordered the murder of Fat Pete Chiodo for the windows case,but chiodo due to its weight survived and flips,
In the 1980s the Jersey Crew gave to Corallo only 50,000 a year to the family,would be enough to order them to pay 10 % of annual profits,but Casso gave the "Whack Jersey" order,so Accetturo and Ricciardi flips; Al D'Arco understand that will be killed so flipped with his son joe.

The Colombos because of Carmine Persico nepotism triggered a war that scuttle the family, The Gambino because of Gotti and his long tongue had the high-ranking rat Gravano that flipped because Gotti will gave all the blame on him;the Bonanno which until 2004 had no rats, after Massino flipped there was a chain reaction, only the Genovese with only 6 rats remain the most stable families.

For philadelphia is even simpler, Scarfo Sr. ordered to whack Salvie Testa for a stupid newspaper article, when Caramandi and DelGiorno were arrested knew they were sentenced to death and tried to save his life, the bloodlust of Scarfo was also disgusted his nephew Leonetti, that idolized his uncle since he was 8 years old.


In the end it all comes down to that until the 80's, there were bosses who put criminals values of respect and loyalty before the money, and then with the new boss what has changed, and then came the rats. Also because one thinks why me 20,30 years When can testify against my "friends" get me a few years or nobody, is going in Witsec maybe keep the money made with crime,writing books and do the good life.