No one in that family was challenging Colombo because of the backing he had from Carlo Gambino, not to mention no one but Gambino killed Colombo becuase they would have been on the hook for the 1.2 million Colombo owed Gambino which was a TON of money in the early 70s...

Now did Carmine Persico plot w Gambino to remove Colombo and possibly Franzese, that’s very possible....