I work for a local non-profit thrift store, and I am the guy removing the donations directly from good folks vehicles. What I have noticed is these old white folks donating old vinyl records all seem to have a very large percentage of black artists in their collections. Something like 20% of their collections are black artists.

I buy the 70's and 80's vinyl that is in good shape, and I have most of the artists listed by the OP. All great music, and those 70's records sound fantastic on my 1973 Yamaha NS-670 monitors.