Unless you are well isolated, bands of scroungers will eventually overwhelm your farm, stealing crops & animals, maybe killing you in the process. The Haves will have a serious problem with the Have Nots. There will be far more of the latter than the former.
You may win every battle but the last, as your determined defense makes whatever you've got appear ever more valuable to those determined to take it.
I realize there are places to hide & flourish, but they wont accommodate many, nor will they remain hidden for long, as the cities empty into the countryside searching for food & relative safety from the jackals. The jackals will follow, if they do not lead the way. Once you are discovered, your peril increases dramatically.
I would expect a very, very large die off in the cities in days or weeks.
Those of us that have spent years and have experience in subsistance level feeding stand a pretty good chance.
/johnny
Agree.
Thus it is critical to know your neighbors and be prepared to band up like the settlers did the last time we fought savages. Also, no one said you and your neighbors had to sit inside the house waiting to be individually picked off. The best defense is a good offense.