Speaking as someone who grew up in a family that idolized homesteading, and who now has a very abundant garden, I do think we should be careful with promoting the ideal of food self-sufficiency - at least on an individual level. Gardening is a lot of work. Most people don’t even have enough space to produce any meaningful amount of food. Yes, you can try growing some beans on your balcony or something of that sort, but if you factor in the price of soil, potting materials, fertilizer, etc and time spent, it’s hard to justify compared to just buying the food in stores, and it certainly won’t be enough to feed yourself in a famine.

If you do have land, one thing you could try doing is looking into trees that produce food, because trees tend to be pretty low maintenance and abundant producers. I’m personally growing breadfruit, moringa, and ice cream bean, all of which are vigorous growers and should be abundant food sources once they’re big enough. (Though I live in Hawai’i, and many places will likely have too much frost for these to survive.) You can also go with edible weeds & invasives - every area has at least a few of those. Jerusalem Artichokes (/ sunchokes), for instance, are a plant in the sunflower family native to North America that produce an abundance of roots and are virtually impossible to remove once they get going. I’ve personally considered keeping some air potato starts on hand in case things ever get really desperate, since they’re highly invasive and produce an absurd amount of edible rhizomes.

It’s a good idea to look into plants native to your area that are edible (even some weeds you consider grasses can be edibles) and lesser known fruits / vegetables / leaf greens in general. The food grown at supermarkets is generally there because it does well on large scale farms with plenty of pesticide, and more importantly, stores well. But there are hundreds (if not thousands) of other edible plants that you will never see in a store, and in many cases they’ll produce food far more efficiently than seeds from a grocery store tomato. You also have to note that a lot of produce sold in stores are from hybrid varieties that won’t be true to seed; if you really want to be food self-sufficient, even if you do just want to grow green beans and tomatoes, you’re still going to want to look into heirloom seeds and seed saving. Finding varieties that grow well in your area is also something to consider, as again, grocery store produce is bred for mass production and won’t necessarily do well where you live. Plus, if you’re going to go through all that effort, you may as well grow something that brings you more joy than russet potatoes. E.g. I’m very fond of this heirloom Italian purple green bean variety which is more or less stringless when young and produces abundantly here.

I think there’s a good reason so many communities have moved towards specialization. It’s simply not efficient to have a few people (or even a large family) trying to do everything they need to do to survive. What we should be doing is establishing mutual aid networks for when things go bad that include farmers, people with building know-how, blacksmiths (and yes, those are still an actual thing, speaking from personal experience), etc. If you have free time and want to get your hands dirty, by all means, start a herb garden, plant some potatoes, or whatever else - but be aware that it’s a lot harder than it sounds, and realistically, the vast majority of people in the west do not have access to enough land to grow a significant amount of food.

Edit: Had to rush this post b/c I had to leave the house - want to clarify that this wasn’t meant as a rebuke of the OP so much as sharing my thoughts on gardening as a whole.

Also, one potential solution for the lack of space issue is finding members of the community who do have space but no time to make use of it themselves. At least where I live, this is a common situation, but I don’t live in a city, so it probably won’t be much help to those that do.

I think learning how to grow our own food is very important, but just as important is organizing locally and figuring out the logistics of doing so.