I think part of the problem is that NC counties don't maintain their own roads:
"North Carolina has the second largest state maintained highway network in the United States because all roads in North Carolina are maintained by either municipalities or the state."
https://en.wikipedia.org/wiki/North_Carolina_Highway_System
I think NCDOT just doesn't use reflective paint. Maybe it's more expensive. I see folks complain about it frequently.
https://old.reddit.com/r/asheville/comments/18ro7lx/why_does...
https://old.reddit.com/r/raleigh/comments/12ehtj6/rain_and_r...
A video of 3M reflective paint that is designed to work in both wet and dry conditions (skip to 6:40):
https://youtu.be/4iY8JqHN-kI?t=400
A related issue you may have noticed is the large amount of trash on our roadsides. This is again because roadside trash pickup is maintained by the state and the budget for roadside cleanup has been de/underfunded since 2008.
Relatedly, recently my wife mentioned seeing a vehicle with large boxes on each side and wondering what they were. From her description, I tracked down that they are a fleet maintained by a small company that measures road marking reflectivity:
https://www.beckenterprises.com/services/
So who knows, maybe NC is finally doing something about the road markings here.