[Retric]

> defense being essentially useless is still dead wrong

That’s not my conclusion, it’s that defense roughly counters the otherwise overwhelming advantage of attackers.

> round the clock watch watch setup by a neighborhood

That’s assuming a great deal of cohesion in your post apocalyptic scenario. I have no problem saying large communities provide a significant benefit, but that’s a product of a working society not something you would see after say a disease kills off 99.9% of the population.