Somehow they managed perfect forward secrecy.
For a while.
You can’t have a network with more than one cell where no one outside of the cell knows that it exists, and without those people using a communication method to people in the cell that at least one person in the cell knows exists. And when you minimize down to the minimum contact, the network is very much non-resilient: its hard to discover and roll-up, but (especially if the cells are doing high-risk functions, which is probably why you want to do it) its also easy to disintegrate accidentally, even without being discovered and rolled-up.
But practically there's a whole bunch of problems as you say - you've no idea how many - if any - cells exist, they can't coordinate on which one picks up a particular target, the communicator is obviously at risk from being tracked down, how do you tell people where the radio broadcast is, authorities can obviously listen in once they've found the broadcast, etc.
Couldn't be done by sending messages encrypted with private key and the cells decode it with public key?
Then the problem is: How to trust public keys to have been provided by the "right" correspondent, and not someone from another gang or law enforcement?
Cell systems have order, but only where the most risk is imposed. Lesser risk, less order. Infact, too much order imposes far more risk.
(Btw, you've been shadowbanned a while ago. I'm only mentioning this, because your recent comments seem sane as far as I can tell.)
I've only ever heard it on an episode of Monty Python. Wonder if it's just a UK thing.
When properly done, such organization is almost impossible to find. I'd not be too sure about them not existing. The idea is well known, so someone must have tried it at least.
The Crips and the Bloods are kind of like that cell structure, but cells have internal beef all the time. If you had different cells have no communication, that would happen way more as they try to expand
Think of a cell like a class in programming. If a class has a bug you can fix the bug, or make a new class with the same ins and outs. Never have to restructure the entire code base. Properly made classes don't leak to other ones. Worst case internal beefs take down prod for a bit but they don't take down the entire program
Perhaps you are in it for the ideology? Or perhaps they pay you?
My sense is that it has become a bit more lax since Apple has grown and, well, let's face it, Steve is no longer with the company.
Or you just have your buddies enact violence on the friends/relatives of anyone caught squealing.
"Why am I Mr. Pink?"
The standard playbook for rolling up criminal conspiracies is to arrest a low level member, offer him a reduced sentence in return for testimony, arrest the next guy higher up based on that testimony, etc. (The only way to prevent that would be a fully trustless "cell" structure where none of conspirators know each other, which has never been done in real life.)
You will notice none of this requires communications intercepts. This is because the feds are simply lying when they say encryption prevents law enforcement operations.