The disparity between developed and non-developed countries can be attributed to various factors. Non-developed nations struggle with brain drain, as skilled individuals migrate to developed countries for better opportunities, leaving their home countries without the means to improve.
More education, means smarter people, means more technology, means more development.
Steady Population
If the population of any country/nation grows to fast, it cannot keep up and there will be no time to keep up. A country with a steady population is able to manage better which allows for "time" to develop.
Higher per capita GNI
This means that the country makes money. If you have money, you can develop.
Industrialized
Economic systems that allow for jobs other than those related
to agriculture do better because of the growing demand for technologically advanced products.
Infrastructure
Infrastructure is often funded by the government
for the common good and helps fuel the economy.
Examples are roads, bridges, telephone lines.
How a Developing Country can get on the
path to becoming Developed:
First, they need to establish a good government with a central bank that has its own form of currency. Then, they need to subsidize a variety of businesses - from technology to farming - to give them a jump start. And let the economy grow by itself.
Non-Developed Nation
Political Instability
There is no time for an economy to grow if the people and political system has no consistency.
Brain Drain
Smart people in developing countries leave to get better jobs in developed countries. Good for them, but the country left behind isn't any better for it.
One-Crop Economies
There is no other way for these countries to make money and if the crop goes bad, they make no money.
Rapid Population Growth
New technology, housing, and education systems are possible to make, but they take time, and people grow exponentially.
Limited Resources
The way any economy grows is by acquiring revenue, but if they don't have any means of revenue due to limited resources, they are stuck in place.