You're not really disputing the fact that after 2011, the state flipped from being slight majority democratic votes with a slight majority of democratic reps (as it should have been), to slight majority democratic votes with a large majority republican reps (as is a completely skewed representation).
This wasn't caused by Democratic voters flocking to the big cities of NC. It was caused by gerrymandering.
I'm not commenting one way or the other because we don't know how out of whack the districts were before 2011 due to the Democrats. Well, actually we do know that multiple times over that decade there were court battles & redrawing because of how bad they were, but I don't know enough about NC's geography to speculate beyond that.
If the majority distributes among itself the things of a minority, it is evident that it will destroy the city. --Aristotle If we did all the things we are capable of, we would literally astound ourselves. - Thomas Edison