They don't consistantly win (read: dominate) only BECAUSE of the parity of the league. Step back and take a look at the ACC's record against other conferences, not against conference play, and you will see that the ACC has consistantly been a very strong and tough conference.
For example, the SEC is considered one of the toughest football conferences, yet holds a decidedly LOSING record to ACC teams over the past decade.
Much like in basketball, the ACC beats ITSELF up because it is balanced (for the most part), wheras teams like USC get to seem dominant while playing a semi-soft PAC 10 schedule. (Nothing against a great USC team, but the PAC 10 can't even spell defense). Of course any above average team will dominate the PAC 10, therefore USC has consistantly (lately) dominated their conference.
That wouldn't and won't happen in the ACC.