There is a corollary to this (something that naturally follows), and it is this:
Grandma’s descendants today would not have a hope of surviving the next Great Depression (coming soon to a nation near you).
Because their supply chain is anything but local, and they know how to do stuff-all.
You see, great depressions are very unforgiving, and mistakes can be fatal. The ‘not knowing how to do stuff‘ is the worst part. Now, is the time for learning, when mistakes are not quite so serious. And the best way to learn is to do.
So, do localise your supply chain (and there is nothing more local than your back yard), make mistakes in the doing, and learn from those mistakes.
That does not cover everything of course. The next Great Depression may be due in part because your back yard (and the surrounding region) may be rendered useless for growing food (the actual reason for that occurring, is immaterial). Your only hope then, will be to join the hordes of migrants from your street, village, town, city, or region, looking for somewhere else to put down roots. I really hope that you are prepared to at least consider that prospect and not decide to simply stay put and starve when the time comes.
The way to learn, is to do. The time to think about it, is now.
Added after publication:
Hmm… maybe people won’t know what I meant by ‘stuff-all’. Maybe it’s just an old pommy saying. I googled it and it came up with nothing, but actually that’s exactly what it means; nothing. It’s just a polite(r) way of saying this …maybe if I had stuck the word ‘sweet’ in front of it?