This is such a good question. There are so many variables that there are no easy answers. Here are a number of points that will help you formulate your own opinion.
First, all nations rise and fall. So, it might be good to recognize that not all nations who are powerful and wealthy now will stay on top. Think of Greece, Rome, Persia, and even England. There is a self-life to all nations. Also timing is very important.
Second, natural resources play an important role. Nations that have natural resources and more importantly the ability to cultivate these natural resources will do well for the most part. Nations, which have little resources or are incapable of cultivating them, will be weaker and poorer.
Third, technology is another very important factor. To the best of my knowledge, I cannot think of a wealthy nation that does not lead in technology in some way or another.
Fourth, there is a principle that works for the most part - wealth begets more wealth. For this reason, often times wealthy nations are able to invest and grow in wealth more, whereas poorer nations have a hard time doing anything.
Fifth, from a point of view of supply and demand, wealthy countries have good or services that other nations want. For this reason, they grow in wealth.
These points should get you started.
Thank you! This gives me some numbers to work with in regard to Singapore.
Take Singapore as an example.
Although she has no natural resources, she still has a rather strong economy which comes from transshipment.
Port authorities constantly improve the technologies and the staff service at the various ports of Singapore