I posted this response to the "Why was Bo so important thread." I wanted to repeat it as a forum since I was so late on that thread. Particularly what I learned in the last paragraph.
I was going to say 1969 was what gained Bo his notoriety also but then I thought a lot more about it. I believe that it was the intensity of the rivalry during the 10 year war. Many close games highlighted by the 1973 tie which was chronicled on a special on BTN or ESPN, can't remember which.
During those 10 years TTUN's lowest final ranking was #9 and OSU broke their heart a number of times. Archie finished 3-0-1 against Bo. The games typically were defensive, hard hitting battles. The intensity of the games and what was riding on them made them a national must see. It was always the feature TV game along with Nebraska-Oklahoma on the Saturday before or after Thanksgiving.
As a point of reference, OSU and TTUN had a total of 17 AP final rankings in the Top 10. The entire SEC had only 18. Think about that for a moment. The national powers in those days was a short list - OSU, TTUN, Alabama, USC, Texas, Oklahoma, and Nebraska.