I get what you're saying but my point is...
What kept America from being a collection of countries on the continent like Africa has a collection of countries on that continent?
If it was all about land mass and resources, then Africa should have recognized the collective power they would have if they became something similar to the United States (such as a United States of Africa).
There's a lot more to it and I don't agree that there can only be a certain number of world powers. It depends on so much more than what you're willing to consider here.
It is leadership, agendas, internally within a nation and the upward mobility of your people and the opportunity that your country has to succeed from competitive fields (science, innovation, production, exporting of goods, etc etc)
There's a lot of things that go into the strength of a nation.
It's a good question, federation.
Many former British empire territories are organised as federations: the US, Canada, Australia, India, Nigeria, and Pakistan to name a few. They are as you say a collection of states that united to form one federal country.
In this map, in green, we have all the federated countries in the world. One thing that strikes me immediately is that the majority of these countries are very large. Russia, Canada, the US, Brazil, Australia, India, Argentina. Out of the top 8 largest countries in the world, 7 - all those listed except China - are federations.
So federation seems to be an efficient way to govern a large landmass. But we should also look at the colonial history of these federations:
Russia was an empire in and of itself, and whatever it conquered was just directly absorbed into the Russian state. The native people were Russianised and everybody became Russian-speakers with some acceptance of Russian culture.
Canada was colonised by the French and the British, until the British took the French part of Canada in 1763. Since 1763 to its independence Canada only knew one ruler, Britain.
The US was colonised by the French, British, and the Spanish. The British held the Atlantic coast and so had the best part of the US; the lands that France and Spain held were much harder to access. After independence the French sold their holdings to the English-speaking successors of the 13 Colonies, and they conquered the Spanish parts later on too.
Brazil was colonised solely by the Portuguese and has always been a Portuguese state of Portuguese-speakers.
India and Pakistan were colonised by a number of powers - the Portuguese, the Danes, and the French - but they only ever held tiny little pieces, no more than a city or two each; Britain had all the rest. English still carries official language status in both countries, and its spoken by about 250 million people in those two countries, about one in six people speak English as a second language.
Australia was colonised solely by the British and has always been a British state of English-speakers.
Argentina was colonised solely by the Spanish and has always been a Spanish state of Spanish-speakers.
So all of these federations have a great deal of history in common, their colonial history of being dominated basically by just one power, and that power left a lasting mark on them, influencing their language, culture, social structures, legal system, constitution, etc. It made sense for, say, California and New York to join the United States together, or for Punjab and Tamil Nadu to join India together, or for New South Wales and Western Australia to join Australia together. Because its all one big connected landmass and they had so much recent history in common and so many institutions and laws and systems left behind by the colonial power also in common.
African countries on the other hand didn't go through the same experiences. There were so many different powers with sizable holdings in Africa:
It's a patchwork of disconnected and small states rather than one big unified bloc like elsewhere. The only places both big enough and governed by a single colonial power were French West Africa and British South Africa. But we also have to account for how diverse Africa is as well. Everywhere else in the 7 federal countries I named, India and Pakistan aside, is practically a monoculture. So there was no ethnic barriers to federation either. Of course there are significant ethnic minorities in Brazil and the US for example, but they basically didn't have any political rights when these decisions were made; it was all the white people who made those decisions, and all those white people were basically from the same background.
So the real comparison I think is why India and Pakistan federated when they became independent but so few African countries federated. In the case of Pakistan, it was having a common religion that drove them to federate; Pakistan was founded at its inception as an Islamic republic. African countries on the other hand tend to have many religious identities. Nigeria is a good example, about half of all Nigerians are Muslims and the other half are Christians.
That leaves India. Which has 30 different ethnic groups, languages, and cultures with at least 1 million members each, and over 1000 different groups overall. With several different religions as well. India would not appear to be a candidate for federation, because it is as diverse as Africa is. But I think the reason it happened is that India has a history of unification, on several previous occasions in its history:
So the precedent existed for a federation since large parts of the country had been unified on many occasions over the previous 2,000 years of history.
that is the single greatest achievement of the Australian government since 1990. The guns were banned in 1996. Since then we've had 0 mass shootings. 0! It's been 25 years, not a single one. It's so hard to get guns that our crazy white supremacist cacs have to actually go overseas to carry out their plans, like the guy who shot up the mosque in New Zealand. That's a win - when even your most dangerous and radicalised terrorists find it so hard to get guns over here that they have to go to foreign countries to do their terrorism.
