Economic Growth and Developing Countries
Economic growth theory is largely based on development of the model put forward by Solow. The Solow model has technological advances as the basic driver of growth, with the ability of countries to apply that technology controlled by capital, labour and know-how. The Solow model assumes that countries are large enough that gains from specialisation of tasks are already exhausted and hence technology change is the only long term driver of growth.
Developing countries mostly have very small economies; over half of developing countries have economies less that 1/100th of the size of the UK economy.
It is very unlikely therefore that these countries meet the assumption of the Solow growth model of complete specialisation. The small size of these economies prevents specialisation of tasks to the degree that occurs in larger economies, resulting in an economic efficiency disadvantage. Small countries can overcome this problem of small scale by trading with other countries, but this only works in the absence of trade barriers. Unfortunately most developing countries also have high trade barriers.
I would argue that the combination of small domestic market scale and high trade barriers is the major cause of growth problems for developing countries. The development success stories are countries that are either very large (India) or have low trade barriers (Singapore) or both (China, Turkey).