It's hard to think of a similar dual dominance anywhere in sports, much less a pair of teams close enough to share barbers.
When the ACC expanded and took in basketball powers Louisville and Syracuse, the sentiment was that the conference was going to be much more powerful and that perhaps Duke and UNC would no longer dominate.
Well, not yet, or at least the perception of dominance is still there:
Sports Illustrated has picked Duke and UNC first in the preseason. UNC has been a bit down lately to be sure, but that will not be the case this year.