This does sound quite scary and impact of such a even would cross the impact what COVID-19 had on all of us.
Seems like it could require additional police presence, and they'll find it difficult to be effective without radios. We will need to look at centuries-old playbooks for virtually all aspects of life, temporarily. Hoaxes will spread without rapid fact checking.
> Hoaxes will spread without rapid fact checking.
They already do. I think you have found the silver lining: hoaxes will spread a lot slower.
And these have / are already happening, so contingency plans are already there, or should be made. Water supplies have been failing in a lot of places due to droughts, heatwaves, and dwindling supplies. Infrastructure took a big hit when COVID started, in part because some people started hoarding (toilet paper, for some reason), but the bigger one was "just" because people changed their habits a little - buying a little extra (toilet paper), working from home (lunch options), baking their own bread (flour), etc. And the office real estate issue took a hit as well, but I don't think anyone will really miss that.
Besides that, the biggest risk will be other people. We've seen in recent history that it takes only a small disturbance - a natural disaster, a protest gone violent, a football match - for people to stop following the social contract. It's often depicted in zombie survival themed media, people losing their morals quickly for their and their family's survival. And with Covid, it wasn't even survival, it was toilet paper.
India and lots of other countries have a lot of local agriculture and would probably be fine. The US and other countries highly reliant on centralized agricultural production and transportation? Uhoh.
Idk from my understanding of natural disasters, failed states, and others, it seems to me that people continue to form social contracts continuously. It's kinda our whole thing, as a species. People absolubtely can be brutal, but a majority of people just kinda try to keep going, and often do extrodinary things to help people in their community continue.
We will regress much further than the 1940s, we don't have living knowledge of how to keep complex systems working that way, we will need to relearn all of that while in the midst of absolute chaos. The main issue won't be technical but social, when civilisation is collapsing it's pretty hard to maintain order to bootstrap these complex systems with pen and paper...