As far as I'm aware there isn't one clear answer to why there was such a delay between Bellomo's release and his ascension to boss. It could just honestly be due to his post-release restrictions. Some guys, like Andy Russo, are very cautious about that. Bellomo was released to a halfway house in July of 2008 and got a job working as a paralegal. He was finally released from federal custody in December 2008, but he had three years of supervised release to complete - so he got off restrictions in December 2012.

It could've also been for personal reasons. His wife died in 2013, so that could have contributed to the decision making process.

The date of c.2014 is also just an educated guess. In January, Gang Land ran a quote from a law enforcement source saying they had been carrying Bellomo as boss for over five years, which would put him becoming boss sometime between 2010 and 2015. In early 2014 the Wall Street Journal ran a quote by a former prosecutor who said the Genovese family was still 'likely' run by a panel, so that leaves enough room for doubt that perhaps Bellomo took over before 2014. In September 2014, Gang Land reported that Peter DiChiara's social club had become a prominent meeting place for high-ranking Genovese figures over the past year. In 2016, Gang Land quotes law enforcement sources attributing that activity to people coming to see DiChiara because he was Bellomo's consigliere and street boss. So it's possible Bellomo became boss in 2013. That would've been just after he got off parole.

At the end of the day, we just don't know. That can probably be chalked up to the secrecy with which he operates. I'll finish up on two quotes found in Gang Land early this year, first from a law enforcement source:

"We've carried him [Bellomo] as the boss for more than five years but I don't ever recall picking him up on a surveillance, which speaks to incredible discipline on his part. He's a very slippery guy who seems to rule in isolation."

An underworld source told Gang Land in January of this year:

"He's like the invisible man. No one ever sees him. No one ever says, 'I saw Barney here, or I saw Barney there, the other day.' But everyone says he's the boss, so I guess that's right. Can't prove it by me, but if he is, he's a great one."