I would argue it is better to have friends and/or relatives with a farm than have your own. Kind of like a lake house, vacation home, or beach condo. We’ll all move in together and do the chores and provide necessary security if things fall drastically apart.
Better have that conversation before the SHTF. Not everyone with a farm is thinking they're the resource du jour for whomever decides "times are hard enough now I think I'll go hang with cousin Bob or ex-neighbor Sandra." Generally, those who want to extract goods from a Common Resource need to determine, first, that they have rights to that resource, and, second, at what cost. If you're not contributing to growing the wheat and grinding it and baking the bread, it's pretty presumptuous to expect to show up to eat when it comes out of the oven, on just a promise to help produce the next loaf. ("Little Red Hen." Remember?) This is a conversation I have had with my grown kids and have prepared for, accordingly. I don't anticipate taking in many strangers, or any old neighbors from my suburban days. I do anticipate helping less prepared neighbors scale up, building local resiliency and community.
2.
If we are talking immediate industrial collapse with no ATM’s, no grocery stores, and no gas stations then even a Mormon storage of a years worth of food will be a dicey survival prospect.
The point of a stored supply of food is to make survival possible for that year, while getting the crops in and out - or to supplement grown food for that year while scaling up to fill the increased number of mouths at your table. Or to keep everyone alive in bad growing years. Yes, it's dicey, especially in the city or suburbs, but it provides better odds than no food storage and no garden, right?
3.
Neighborhood localism will not take hold until unemployment climbs markedly. Banking failure is going to give us a new monetary system one fine day and promises of repayment and pensions will be re-evaluated. I will be poorer but I would rather rely on the people I know and stay put. A neighborhood organization can negotiate with the city powers that be (Police, Utilities, Sanitation) for essentials.
I'm a big fan of localism. The question is always: what do you bring to the table when the chips are down and everyone is worried about survival? Those who cannot add anything are a resource drain. A community with enough resources may be able to afford to carry such persons - and certainly a community will have compassion for those who are mentally or physically diminished, as long as possible - but the able-bodied will/should be expected to contribute to building up the Common Resource if they intend to withdraw from it. A coordinated suburb can grow a lot of food by taking down fences between houses and opening up common ground to grow both plants and animals. But somebody needs to know how to do that, and whoever does is going to be the proverbial one-eyed man in the land of the blind, with the power that goes with it. People of good intent ought develop knowledge and skills to be that "man", or one of the leadership corps, in order to set the humane tone that is too easily lost when people become desperate.
I would not bank on the 'burbs of the US functioning as caringly as South American cities. We have further to fall, from our high place on the hog, and therefore greater fear - and we seem to be coming apart more than pulling together these days. I expect some communities will unite and do quite well, and others will fracture and become oppositional. The difference is going to be early leadership; again, that goes to whomever is best prepared to help lead the community into a survival discipline - and it's inevitably going to require defining who is "in" the group and who "out." There is no way your suburb is going to be able to help 200,000 urbanites who head your way looking for something to eat, or for water if the highrise's power goes out.
Because the circumstances of a decline are so variable, and unknown ahead, I wouldn't assume police, sanitation, water, electricity, heating fuel, medical care, or food will be available - or available as needed, or at costs the community can afford. It's at least worth the thought exercise to envision some substitutes or work-arounds. Ideally with neighbors if the plan is to work together in a decline. (This is also a good way to suss out who is already thinking about preparedness and who thinks you're nutz.)
The 5 core foods you need to know how to produce in order to provide yourself all of the protein, vitamins, enzymes, and minerals required to keep yourself alive are: corn, beans, potatoes, squash, and eggs. (See: Deppe, "The Resilient Gardner.") It is my opinion that everyone ought to at least learn how to grow those without outside inputs, and learn to keep them going without returning to a store for either seed or pullets. That's minimal resiliency. Without such ability, I don't think a person is in any meaningful way either resilient or free. It's much better to learn how before survival depends upon getting it right.
Add to that ability the "Mormon storage of a years worth of food" and survival odds go up at least a few notches. And even if our future never devolves into an apocalyptic nightmare, as the economy fades and resources go with it, being able to produce core essentials reduces stress and cost, smoothing out economic and resource blips and gaps, while buying time to learn and scale.