That's because they are not "mob" bosses, as such. The Carlton Crew is just that; a small crew of mid level criminals, and all the figures you named operated in groups that are a far cry from the size of even the smallest LCN families. Dennis Allen was a pyschopathic nutcase, Domican was a heroin dealer and Neddy Smith was a heroin dealer with delusions of granduer.
The exception could be William's who personally committed his first murder; after that he farmed them out (which didn't work out to well anyway; two of his hitmen flipped on him and he ended being bashed to death with a metal bar ripped off an exercise machine in prison)
Many Australian media sources like to blow them up and make out like they're so much more than they are/were. In reality, sure there's millionaires amongst them, but they operate on very different plain from "the mafia".
I may cop some flak for this, since even more then a decade after his death there's still a lot of groupies: Gangitano was a joke. He was a private schoolboy who came from a good family, who decided early on he wanted to be a gangster; he spent his life posturing and hanging around guys worlds heavier. The only two murders I can remember him being linked to was Greg Workman, whom he shot over something like a $100 debt at a party surrounded by witnesses (yeah, real tough buddy) and a prostitute he administered a "hot shot" to, and yet his "reputation" preceded him for many years.
By all accounts, Mick Gatto is actually a stand up guy though. Down to earth and media shy (with the exception being his book
I, Mick Gatto "setting the record straight"

) Regarding the Veniamen murder, if the official line is to be believed, it was a case of self defence with Veniamen entering the restaurant and confronting him. He claims he wrestled the gun out of his assailants hand, causing Benji to "come off second best", as he put it. Ive never really bought that argument, but Benji Veniamen had a terrible reputation at that time, and was suspected in amny murders himself. He now works as a construction consultant and in company dispute abitration. Which basically means he uses his rep to sort out problems between companies and corporations.
A funny story (IIRC); apparently back in the late '90s, he and Mario Condello fell victim to what was basically an elaborate 411/Nigerian scam. They cut their losses and never spoke of it again.

For the record Furio, a chart of the Carlton Crew would be almost completely horizontal, since despite media reports painting "leaders" there is only the barest semblance of structure. And despite reports of Mick Gatto's leadership, the Carlotn Crew as it operated in the 80's and 90's is allmost completely gone. There are numerous other, more serious players in town who dont care for sitting around in Lygon Street all day. There's a reason Chopper Reed called them "fairy godfathers".