Richt, Urban, and Saban all entering the conference in the early-to-mid 2000s doomed him.
Nobody likes admitting it, but a huge part of Phil's success in the 90s was because he got to recruit against guys like Ray Goff, Gerry DiNardo, Mike DuBose, and Brad Scott. Even Spurrier, who had his number on the field, was never known as a relentless recruiter. He was able to go all over the southeast (and California too - Southern Cal was bad in the 90s) ex-Florida and get whoever he wanted. Once the conference's roster of coaches got deeper, combined with the fact that I think he took his foot off the gas after 1998, guys started running circles around him.
The 2008 SEC coaching class is kind of insane
Saban (GOAT)
Meyer (2 NC)
Miles (1 NC, another NC appearances, 2 SEC titles)
Richt (2 SEC titles, ten 10-win seasons, maybe the best coach to never a title)
Fulmer (1 NC, 2 SEC titles, 152 career wins)
Petrino (four 10-win seasons at non-traditional powers)
Tuberville (undefeated season, SEC title, 159 career wins)
Spurrier (1 NC, 6 SEC titles)
Rich Brooks (Built Oregon with his bare hands, made Kentucy respectable, NFL HC, 130 wins)
Bobby Johnson (led Vandy to first bowl in 26 years)
Houston Nutt (over 100 career wins)
Slyvester Croom (uh....)
Like holy hell, talk about a deep coaching circle.