There are many ways the S could HTF but I think they all have one thing in common: in the first hours/days/weeks, many people will die, including people who are well-prepared.
In the medium term, the people who have stockpiled food and equipment and knowledge will have a greater chance to survive (but not guaranteed).
In the long term (years to decades), I don't think a "person" will survive at all. Survival will require a community of "people" with a good mixture of skills (with the skill of "getting along with others" being very, very important). Bandits may survive a couple of years by preying on others but that is not something that can survive a decade or more - that requires proper civilisation.
For a very bleak view of this, check out the British movie "Threads".
B
In the medium term, the people who have stockpiled food and equipment and knowledge will have a greater chance to survive (but not guaranteed).
In the long term (years to decades), I don't think a "person" will survive at all. Survival will require a community of "people" with a good mixture of skills (with the skill of "getting along with others" being very, very important). Bandits may survive a couple of years by preying on others but that is not something that can survive a decade or more - that requires proper civilisation.
For a very bleak view of this, check out the British movie "Threads".
B