Well, notice that they are composed of thousands of small crowds in separate venues. We laugh at a few hundred in each place or even an afternoon march of a thousand or so, but if they are organized in this manner into manageable groups, (think squads, platoons), then the venue is controlled via orchestrated group think. With phones, services like Skype, and the Internet, they stay in contact and further coordinate. Who knows what texts are being exchanged between them, even within the smaller groups? They are all glued to phones 24/7.
They are also receiving credit card donations from all over the world. Foreign supporters are ordering take out for them, via credit card. This is sustainable. They really are citizens of the world, in practice.
Your defensive cell analogy is on target, IMO. You can pick them off individually, but as a whole, they are quite vital.
I predict the cold weather and Christmas coming will wane people’s interest and they’ll just disperse.