A) A bit of a generalization, but certainly there's truth to this.
B) Such as? Not being contrarian for the sake of it, but Jim Crow was still rampant in the south. Schools were segregated. I'm not well versed on the economic indicators you speak of, but socially, it's hard to argue it's worse now than in 1962.
And this is from someone who thinks the racial divide in the US is still huge.