Ironically, this style of O came to the Big 12 from the SEC. When Bob Stoops was the D coordinator @ Florida, he said that the toughest O to defend in the SEC was the Hal Mumme O @ Kentucky. When he took the OU job, he hired Mike Leach off the Kentucky staff and this one move morphed a conference that had made it's bones on power running attacks into air raid central.
This has also resulted in Big 12 D's having to completely change the way they recruit and scheme. The high scoring games now prevalent in the conference are more a result of D's being stressed in open space by highly athletic and fast O's then they are of inherently bad D's.
I think you are seeing as manifestation of this in recent SEC games, particularly where you have two former Big 12 schools (Mizzou & T A&M), running classic Big 12 up tempo, spread-the-field O's against D's that have been recruited for and coached to go up against more traditional O's.
South Carolina's D was totally gassed and completely over matched in terms of scheme and athleticism. I can only imagine what Baylor's O would have done to the Gamecocks.