Yes, but... once some degree of peace and independence is achieved, social improvement happens at an astonishing rate. Take Iran. At the time of the Revolution

Yes, but... once some degree of peace and independence is achieved, social improvement happens at an astonishing rate. Take Iran. At the time of the Revolution in 1979, it was one of the poorest countries in the world. The birth rate was above 6 (I find birth rate is a very good proxy for economic/social progress). It dropped from above 6 to under 3 in just ten years - a feat that took England 95 years to accomplish. Today, Iran's birthrate is less than Europe. This is a result of (relative) peace and independence. China is a particularly wild example. Per capita income there has grown about 15,000% since 1952. That's crazy, but it happened.