How did third world underdeveloped themselves?

How did third world underdeveloped themselves?
Did they under-develop themselves or was it lack of will to (help them) develop further? I think that is a matter of opinion and perspective, but while the west, mainly, for the longest time has shown little or no interest in helping the "3rd world" develop unless there was something gain in return, i.e. resources, precious metals, spices, fabric etc., there seem to have also been little interest from some of the "3rd world" countries to actually develop.
Some such as the BRIC and South East Asian countries decided to develop so they went about it on their own and they are coming around nicely, while so-called "developed" world is standing still. By naming itself "developed" aka "superior" it basically stopped developing; its like telling yourself you know everything then you stop learning from that second because you belie there is nothing more to learn.