I mean....it's not like his followers that are still alive/incarcerated haven't like discussed this with anyone in the 50 years since. And they all pretty much say exactly ^^ this.
No I don't think this was like Project Mayhem/Fight Club nor do I think it's some grand conspiracy. I think it had much more to do with the time than anything else - there was a lot going on all at once, very easy to manipulate young people. I think Children of God is far worse than the Manson family, and it started around the same time. Rose McGowan was born into that cult - it may explain a lot.
I don't see parallels to the Son of Sam murders. But I think it's plausible David Berkowitz didn't act alone.
The group that Maury or whatever he was called suggested the Son of Sam killers where part of was called "The Children" and the Manson's cult was "The Family", not that I think they where linked but more part of a trend or scene at the time, that guru guy who invented "The Process" probably had ideas that Manson or others piggy backed onto or found useful.
People recruiting or exploiting people as "assets" whether its because they are young, impressionable or mentally ill is nothing new either.
I found interesting was whether, irregardless of the origins in satanism, amoralism and some sort of sadism, that the drug trafficking, snuff films and money mattered more towards the finish and things evolved from there. Its different but in the ROI the two or three big organized criminal gangs which exist had their origins in pseudo-political Trotskyite and Republic factions which started out doing bank heists for some political purpose and eventually just decided it was all about the money.
There was a certain "template" involved in some of the killers experience and their deaths which has a kind of plausibility for the version of events that suggests there was an organized aspect besides what was trending.
Like they got these guys involved in violent, sadistic, ritualistic acts perpetuated on victims, so they know its not all a bluff, that this type of thing is possible and happens, then they tell them if they ever rat them out to the authorities they are going to do it to their nearest and dearest, details of whom they've provided in pictures or something to their partners in crime in the first place.
I wouldnt be surprised if these groups evolved into criminal operators, dealing in whatever ill shit permitted them to black mail, control or kill and make money doing it. Either that or criminal elements resembling them will have learned from them as a sort of example.