During the dark days known as college football off-season I got interested in looking into the all-time records of the 'major' programs of the Southeast. Most of impetus to do this was derived from sheer boredom, but some of it was from a certain amount of noise coming out of a small agricultural school in Pickens County. Now I don't think you'll hear any Carolina fan making an argument for historical dominance. If I'm not mistaken USC was 1 game below .500 prior to Spurrier's arrival, which is about as good of a definition of mediocrity as you're going to get. As for Clemson, well they have many, many wonderful traditions: getting on a bus, rubbing a (chipped) doorstop of dubious origin, running down a grassy knoll surrounded by grown men wearing safety orange and purple. These are all very wonderful, but is winning a tradition that Clemson can lay claim to? Let's take a look.
So here's the list of 22 major teams in the Southeast and their historical records. First thing I notice when looking at this is all the teams ranked #8 and above would be considered 'good' teams, i.e. I assume these teams are always going to have a winning record. Teams below that I would consider mediocre or worse. Interestingly, only 3 teams have won more than two-thirds of their games. Football appears to be difficult. Also of note, Vanderbilt is only 6 games from a .500 record. Given the state of Vanderbilt football during my lifetime, they must certainly have been fairly tough during the first 50 years of the 20th century.
Now, here's South Carolina's and Clemson's winning % vs the teams on this list. Both USC and Clemson have losing records against the top 8 teams. Overall, South Carolina has winning records against 7 of the 20 teams, while Clemson has a winning record against 6. It is important to note that Clemson has met 6 teams fewer than 10 times (they've only met West Virginia twice, but I think WVU definitely has the advantage in points). So anyway, Clemson has a losing record again 70% of the major teams in the Southeast. Clemson of course has a winning record against South Carolina, having won 66 times in 112 meetings, or a little over 6 out of every 10. What is evident is that neither team can lay claim to a great winning tradition, especially in the within the region, and that both teams have a lot of work to do over the next few decades if they want to move up on the all-time lists.
Check out Winsipedia for more on historical football records.