I really don't think it's some sort of conspiracy: it's just that it's more efficient for someone to grow all your food, someone to make all your clothes, someone to purify all your water, someone to generate all your electricity &c. while you do what you do best than it is for you to learn how to do all of those things, acquire the raw materials and spend decades trying to make a computer from some copper, oil and sand.

I recall that Mao Zedong tried to get every farmer to smelt his own iron, which rather predictably led to a lot of poor-quality iron, and a food shortage.

I get the appeal of self-sufficiency, I really do (one of my dreams is to grow all of my own food), but I think it's a luxury for the rich and inescapable misery for the poor. Modern capitalism has made everyone richer.