Yeah, all these “developing/third world” counties have been around for thousands of years and they are still, “developing.”
well, a developing country is a primarily agrarian one with low income.
In 1850 every country in the world was by that standard, developing. The UK moved of that first and only in the early 1900s did the USA and Germany move out of “developing” status.
China and India as civilizations and cultures have been around for thousands of years. however, as countries they are both new - dating to the late 1940s.