The vast majority of African Americans were descendants of slaves who were not permitted to even learn how to read and write; the Japanese, the Chinese, the Jews, and most of the Europeans came to this country with education, and Entrepreneurial Skills; while African Americans only knew how to earn a living by the sweat of their brows.
https://www.youtube.com/watch?v=pyBZnLuNJ7kWhen this country pulled the plug for jobs in this country, African Americans were stranded wherever they were, and if Detroit was that place, that's the way it was.
Thank God for America, it throws people in a hole in the ground, (over a period of 100 years), and tells them to pull them selves up by their boot straps.