My opinion is that many develop countries (or, as you said: third-world countries) are still stuck in a structural cycle and breaking this requires much more than a wealth of natural resources or "economic luck" (you can't gamble with a country's economy like you do in a gambling game ).

For a country to grow, I think the main thing is have solid institutions and a good governance, but as you said... corruption is truly the main obstacle to sustainble growth on any country. After that comes international recognition and foreign investment... with long-term planning its possible, but like South Korea and Singapore, its take perseverance and sometimes an authoritarian start.

You mentioned natural resources... there are countries with large oil or mineral reserves, but their problem is a lack of economic diversification. When they depend of a single sector, they become very vulnerable to external shocks... they have to create a value chain exporting more than just raw materials, like China did.

And about my country, Brazil... nothing to declare!
I love it very much, but I am deeply ashamed of the direction it is taking