Respectfully disagree - Clemson is at least half the state and probably has a bigger fanbase than SC. They averaged about the same attendance last year even though SC had their best season in decades and Clemson was 6-7.
Does that mean the SEC values half of SC more than it would value adding Texas (no) or West Virginia (prolly)? No. But its pretty shortsighted to say that adding Clemson adds no value to the SEC. SC is pretty divided - adding Clemson probably brings them from around 50% market penetration to close to 100%. Again, gaining a big chunk of SCs market may not be worth that much to the SEC, but saying it adds no value is unreasonable.