The National Syndicate was more powerful back then. If there are any remnants left, they have probably gone legit, or are splintered. Guys/families like John Gotti are a thing of the past but I'll admit there are several criminal organizations now like biker gangs, Russian and Asian Mafias, and some Italian still around.
They couldn't buy the Kennedys. Bobby had to be stopped. So they shot JFK. We have the declassified FBI memo of Carlos Marcello admitting it (which corroborates what Santos Trafficante confessed to his attorney before he died). We have other declassified documents (visit the book site of Ultimate Sacrifice and Legacy of Secrecy) which show that the CIA liaison with the Mafia back in the day was compromised with a $200,000 bribe to disclose the secret coup d'état in Cuba codenamed AMWORLD, which was to take place on December 1st, 1963. The Mafia bought that secret and blackmailed the government from not investigating or prosecuting them for the murder of JFK who they had to stop, or else they would've disclosed that secret coup planned and supported by the U.S. to the Soviets. There's evidence that after JFK's murder, prosecutions against the Mob fell dramatically.
Frankly, Kennedy had enough enemies who jumped at the opportunity to cover the murder conspiracy. But today, I would agree that they don't murder politicians. They use less dramatic techniques like 'character assassination'. But back in the day . . .
P.S. They killed RFK as he would've re-opened the case. There's more than enough bullet holes to disprove Sirhan Sirhan as the lone gunman. Some say he was subjected to CIA mind-control experiments. There was also a security guard at the Ambassador Hotel that day who worked for the mob and is currently exiled in the Philippines. I can't remember his name.
Look the maffia could have killed him, but ask why would they bring so much attention to their organization. I have no doubt that the maffia killec oswald and that was a smart move. Because you have to remember that this was USA 1963 and Huber wanted didnt need evidence to destroy some body. He just needed to make up what ever he wanted and if he had oswald he could have made him confess to what ever he wanted. Which would have been very bad for the maffia at the time. Also the mafia back then was not as powerful as people think.
However, thanks to government policies in attempts to control peoples vices. The governments of the world have turn all organized crime groups into extremly rich and powerful organizations. With Italians and Colombians at the top of all organizations.
You have to remember that this guys are business men that work in the grey area of the world. The last thing they want is stupid attention that will be bad for business. Killing a US president wpuld be a dum move and for certain any made guy that wpuld do something so stupid for sure would get kill along with his entire family to ensure it never happens again.
The maffia doesnt need to kill a politian. They have more than enough money to buy them.