Cable TV was barely in its infancy. The NCAA controlled the football contract for every NCAA school. Teams rarely played outside of their region, and conferences were geographically compact to cut down on travel costs (buses).

USCe was leaving the conference because they felt the basketball ref's were screwing them, the ACC Basketball Tournament was considered to be the preimminent college basketball tournament, and the ACC boasted 3 of the top 5 teams in the country, UNC, NCSU, and UMD. As a matter of fact, the ACC's television contract at the time was the largest in the country because of basketball. The ACC was in the catbird's seat, and that's why GT left the Metro Conference to join it.

If you want to talk about screwups, then that would be the Metro Conference. At it's founding it had Louisville, Cinncinnati, GT, Memphis, and Tulane. Later they added FSU, Virginia Tech, Southern Miss, and South Carolina. If they had added WVU, PSU, and Pitt, that would have become a hell of a conference. That was the missed opportunity of the last 50 years.