In some very poor countries, it's not rational to adopt those technologies because of the cost of labor. The second reason might be the system doesn't reward profit or risk taking. There is a recent study showing that the rate of return on capital is actually similar if you look across countries. It's not that people are missing big return opportunities, but the returns aren't so high in a lot of developing poor countries.
Russ Roberts interviews Robert Barro, Harvard University Professor and Hoover Institution Senior Fellow, on the economics of growth, what the developed world can do to help poor people around the world, and the role of US assets and the dollar in world finance.