Because that is good for the ACC.
Each conference has a team, or two, maybe three, that serve that role. When such a team is riding high, the league benefits; when such a team is down, the league is going to be perceived widely as being down. UNC is to the ACC as Texas was to the SWC and is to the Big XII.
What is most important in all that for the ACC is that UNC football hasn't won the ACC since 1980. In 1981, Ara Parseghian praised ACC football and predicted that the Clemson 10-8 win over UNC could mean the National Championship for Clemson. When the old CFB TV monopoly (that was largely controlled by the Big Ten for the benefit of the Big Ten and the Pac) was broken, the first CBS national broadcast was UNC at Pitt, with sports writers and TV talking heads stressing the rise of ACC football.
If UNC gets its football house in order and starts winning as a matter of course, the ACC will gain in stature with the media and with CFB fans from outside the ACC area.
I understand why especially Dook and NCSU fans but also fans of other ACC schools hate even thinking that could be true. But it is, just like it is true of Texas and the Big XII, Bama and the SEC, Ohio St and the Big Ten, USC and the Pac.
The ACC is the only major conference in which its 'IT school' has never won, never played for, a National Championship in football, the biggest and most important sport. UNC's football neglectfulness has hurt the entire ACC.
