Why did the government intervene to save "them" if "they" were "even beating whites in some metrics"?
Not much of a student of history I see. There was a ~30 year stretch where the black community really started to spread its wings. They didn’t give 2 shits about racism. They built their own communities with strong families, strong businesses, strong morality, and excelled in sports and the arts. They built houses, hotels, theaters, stores, nightclubs, even their own railroad (which hired many whites). Single motherhood was unheard of. It wasn’t until the government convinced them of their own inferiority that they reversed course.
I’d recommend some books, but I doubt you do that sort of thing. Try a docu called Wylie Avenue Days made by WQED, it focuses on the Hill District but is representative of the black community in general in those times, if you can find it.
Edit: Carnegie Library has a copy.
https://iiisy1.einetwork.net/search~...+days&3%2C%2C3