Human migration moved remarkably fast. East Africa had merely accelerated the process, provided it had an abundant population to deploy. This was precisely what Henry Barkley could not imagine, and so he proposed the hypothesis of north-south rivers.
Without knowing the Kingdom of East Africa's population, he used the immigration rate of Cape Colony as a reference and concluded that the Kingdom of East Africa could not have many people. After all, it had been founded less than two years ago. Even counting the colonial period before that, it had only been a few years. In such a short span, East Africa would be doing quite well to have a population of several hundred thousand.
In this regard, Henry Barkley could neither imagine nor understand the immense assistance a whole-nation system could provide to immigration. East Africa had operated its immigration program at a loss for years, pouring European and Far Eastern populations into East Africa regardless of cost.
Such an entirely government-led immigration strategy stood alone in the history of the Western world. Of course, East Africa's great migration was not without precedent. The Far East, for instance, had possessed this tradition since ancient times—the great Hongwu-era migrations of the early Ming dynasty, the migration from Huguang to repopulate Sichuan in the early Qing dynasty... The difference was that East Africa's migration crossed the sea, while the Far East's migration traveled over land.
The United States' immigration rate was also terrifying, but that rested upon the United States' uniquely favorable conditions. Moreover, the United States was currently a typical small-government nation, and matters like immigration were driven entirely by private capital.
As for whether East Africa could assemble tens of thousands of troops from a population of several hundred thousand, that was entirely possible. Most immigrants were unmarried adult