I would imagine people would go into your house + every warehouse, and just start looting everything. Most people do not have a large supply of non-perishable goods and will likely try to take yours.

My point is the "vast quantity of good land" the USA has would be useless in a short-term famine scenario. It takes months to grow food. If there's a scenario in which the USA has outsourced its entire food supply overseas, and that food supply is cut off, unless there's a 3-4 month stockpile of food for every person in America and the USA figures out how to restart its entire farming system in a week, people are dying en masse.

Even if that occurs, there's still going to be riots like COVID-style runs on toilet paper.

That's why food self-sufficiency is critical to national security.