Why have LEDCs developed mainly as exporters of raw materials?

The leaders of the LEDC countries are not sensible enough to realize that they need raw material processing economies, not the low economy of exporting them to other countries who engage their young ones in lucrative processing jobs to the detriment of their own countries young ones. They do not know that they need to create jobs at home by processing their raw materials, add value to them, export them at higher value and improve the standard of living of their people. The leaders of the LEDCs just do not know. They are just plain stupid. That is the reason. Plain Stupid.