system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How did the U.S. rise to a global superpower in only 250 years but counties that have been around for 1000s of years are still under-developed?

The U.S. was a developing country for *maybe* only 100-150 years. After that, the U.S. became arguably the largest economic, military, academic, manufacturing powerhouse the world has ever seen. 

Yet, countries that have been around since ancient times are still struggling to even feed or house their population. 

How is that possible?
gpt
Progress over time isn't guaranteed. A devastating war, plague or simply bad leadership can set a country back decades, and these things can happen over and over again.

The US has incredible potential for building a superpower - the geography is nothing short of amazing. It has lots of natural harbors in both the Pacific and the Atlantic, enough arable land to feed itself many times over, vast resources of all kinds - oil, minerals, gas, you name it. It was too remote to be in any real danger of the other great powers of the time, and its only two real neighbors are weaker states that pose no threat.

It had all the resources and living space it needed to grow into a superpower and all it really needed was good leadership, good institutions and enough time to grow, and that's what it did, with relatively few setbacks while other countries have been perpetually ravaged by wars, famines, disease and tyrants.