He was underboss when he went inside and did a long stretch. By time he got out most of the guys in his era were either dead in jail or retired

When he got whacked he was only with his cousin (owner) and Coppola... Plus his two zip bodyguards (were they his only crew members)

And he just went around bullying the other captains who were all deathly afraid of one man. And that is why he was so easily crushed with zero retribution once he was taken care of

I know he was close to a few captains like Mike Sabella so perhaps that was his power base relying on the crews of guys supposedly under him as opposed to having a large crew himself (like Gotti) he took out Paulie and even when Paul was alive... Chin and Paul had a pact to kill all drug dealers

But other than having Neil as support/ even after Neil died nobody could easily make a move on Gotti due to the number of guys he had behind him.... That's where Galante went wrong, he thought he alone was sufficient to take on anyone due to his reputation alone