The dumbest thing about most "preppers" is that they invariably develop absurd ideas about how their fortress will beat back the hordes they imagine to descend (sound familiar?) yet pay basically no attention to their local council, who would be the nearest level of organization and planning continuance which would allow a practical response if the larger systems failed.
This isn't even speculative: the current the COVID-19 response in America has required local councils and city boards to coordinate, particularly in the absence of any clear direction at a Federal and frequently State level.
Yes. And so far the local responses have been better, or at least did less damage, than most of the more centralized actions. Like the FDA banning almost all tests.
Here's an article https://reaction.life/why-is-germany-able-to-test-for-corona... exploring aspects of centralization vs decentralization by way of comparing the German and UK responses to the pandemic so far.
The German system has centralized advice and coordination from the Robert Koch institute, but no centralized institution to ban local initiatives.
But that's not the standard zombie scenario. Having 1% of the population being somehow sick and dying or a strain on the medical resources doesn't make society collapse.
The zombie scenario is that only 1% of the population is unaffected and society breaks down and disappears and modern humans, humans living after the Enlightement, have to survive in a hostile environment.
I agree with Charles Stross that people don't just bash their heads in a crisis but that they start to look after their own community. But this probably stops after we reach the magical number of 150 people.
After that, other people are not friends anymore and how we deal with them when resources are scarce, well, I'm not as optimistic as he is. Just look at the current mediterranean situation and that's when resources aren't actually scarce.