you had that going back to the 1920s with Jazz
Oh no doubt. Maybe I should of clarified or stated it different but basically I feel like the 1950's generation was the last one that were really "country"(collectively), despite many already living in the north or the west. By the mid-1960's I feel like that shift was complete.
I agree it started in the 10's-20's, but I dont think it was really solid till basically the end of the great migration in the late 60's. Like communities in the north had folks who were already a couple generations deep yet still deeply rooted in southern ways.
For whats its worth my view might be a little different cuz Im from Cali, since we were the babies of the great migration and most of us didnt get here till the 40's, 50's, & 60's, my scope leans a little more towards the second half of the great migration.