This is a FAQ question.
Why is there not one united nation across all of Latin America?
Why did North America split into three countries and Latin America into fifteen, although they were colonized similarly?
Why did the first post-independence Latin American states (Gran Colombia, the United Provinces of the Río de la Plata, and the Federal Republic of Central America) all break up in the 1830's? Why didn't Mexico?
Why did the did only two countries develop out of the Northern Hemisphere, or former British/French colonies, while around 20 different countries developed out of the former Spanish/Habsburg empire in Central and South America?
Why did the Spanish colonies in South America split up into many different countries, while Brazil stayed as one?
Why did Central America balkanize rather than unite?
Why didn't the Spanish colonies in North America form a single nation a la the United States?