There's not actually all that many useful things that can be made in poor, underresourced countries and villages. It's cheaper to buy them from a Chinese factory that is highly specialized at making those useful things in huge quantities and send them via container ship to the place where they're needed. This is as true for random poor people in Africa as it is for me when I buy stuff cheap on AliExpress.

One aspect is perhaps that simple things aren't necessarily cheap. One Laptop per Child struggled to get costs down, whereas a mass market solar panel is not self-serviceable but at their current cost, who cares. Even in the developed world, you get noticeably more bang for your buck if you buy a cheap, basic car than if you buy a cargo bike that could replace it, because of the fierce competition and huge economies of scale for cars. Touch screens are cheaper than seven segment displays. And so on. (Not a snub on the Open Source Low Tech community, their designs look great!)

It doesn't make anyone money...