lot of different therories on what was the "reason" for failure of continuing the 90s run. Many of the things mentioned likely played a part in the program falling back, but its just conjecture. No good way to pin it on any one, two or 6 things.
One thing not mentioned, I don't think, was how the SEC as a league was getting stronger. Like with recruiting. The other teams started keeping the better players at home. Is that because UT fell off or that the home schools were getting better?? The other schools improved recruiting, development and coaching..
It was a lot of factors with one major issue that led to the program dropping and moving into a 15 year cycle of poor performance was the horrible leadership of the administration of the university down through the athletic department. An athletic department going through as many ADs, chancellors and Presidents as UT did from 2003 until Boyd brought in Plowman and then Danny White, is setup to fail. and it showed with the majot program in the AD, football.
JMO