I'd like to remind the Gallery that in 1921
there were still a helluva lot of people in OK ( especially outside of Tulsa and OKC) that were riding horses and mules. there were trolleys, trains, but cars and trucks were mostly for businesses. my own grandfather was delivering Ice by mule and wagon almost till WW2 in small towns.
then all of a sudden you have a wealthy black population that shows up driving cars, dressed to the nines, building nice homes and businesses. taking over damn near half the town. your own poor to middlin's just got more poor to middlin's.
imagine the some of richest black people of Detroit, KC, NYC, Chicago, Cleveland, etc...etc all moving here at within a year of each other. all bringing their own issues here. all trying to out do each other.
the class and social issues were just too much, too fast.
as Monger said,
Desegregation shattered the institutional "Black Economy".
until the 60's there were basically 2 (maybe 3) economies in the US.
white
black
(maybe you can count jewish)