Because he didn't really accomplish that much.
Taggert was 2nd coach at WKU after their move up to FBS - and got them to 7-5 in 3 years. WKU was a very good I-AA program (a Natty and 13 conference titles) and they had a brief adjustment moving up.
USF was good under Leavit but bad under Skip Holtz (because Skip Holtz sucks), Taggert got them to 10-2, but they play in the AAC - and the competition is terrible (Leavit coached them in a much tougher old Big East)
Oregon was coming off a 4-8 year where they had lost 3 games by 3 points each - and he basically flipped those 3 games.
WT isn't a bad coach - but he isn't some miracle worker/next level coach.