@saysfaa I agree with all of your points, when they apply to people who WANT to raise some of their own food. But I don't think it's as easy, or as widely applicable, as you imply.
The expertise; this is the information age, such information isn't hard to find.
Yes, it's easy to look up how to do something.
But I would say "expertise" has more to do with actually knowing how (including experience.)
For an example, look at all the people who try to grow vegetable gardens. The first few years tend to be inefficient, and full of failures in one crop or another. (And by then, some people have given up.)
I do recognize that if it most people to grew gardens, it would be easier for new people to learn, because they would probably have a neighbor who already did. The experienced person can often tell in a few minutes what the new person would spend hours trying to figure out.
The space; about 70ish percent of the US population describes their neighborhood as suburban or rural, most of them have lawns that would be space for a garden big enough to grow vegetables for most families.
You are assuming the lawns get enough sunlight. Houses cast shade, and many subdivisions have large trees that also make shade. Between the shade and the tree roots, this can severely limit a person's ability to grow food.
Also, converting the lawn to garden would mean no lawn.
Whether the lawn is needed will depend on what each family uses it for.
For example, it is not good for children or dogs to run & play in a vegetable garden!
Also, an unfenced yard (especially next to a sidewalk or street) is not always a safe place for a garden: it can get trampled, contaminated by dog waste, things picked by people walking past, and so forth.
The time; I just looked up the average amount of time people spend on social media per day, the amount spent watching tv, the amount spent on sports, leisure, recreation.
Yes, people could do more important things (like raising their own food) instead of those things that seem less important-- but people also have some need to relax and do pleasant things, and not everyone finds it relaxing or pleasant to raise any of their own food.