In an underdeveloped country the problem is that a bureaucrat is designated with responsibility of a specialized area, whether in economy or education.
Another reason exports can not be promoted is because in all likelihood, an underdeveloped country may only be skilled enough to promote the export of primary goods, say agricultural goods.
It is used to distinguish whether the country is a developed, developing, or underdeveloped country, and also to measure the impact of economic policies on quality of life.