Their tradition is hiring washed up coaches who had success at other schools and then getting mediocre results from them.
They've done that 3 times in nearly 120 years of football (Dietzel, Holtz, and Spurrier)... and mediocre is relative. If historically your school had an overall losing record and since joining the SEC almost 2 out of every 3 seasons was a losing season, then 9-5 and no losing seasons in 7 years is not so mediocre. You can argue this is a sad statement on the history of the program all day long, but you can't deny that the program has improved in both talent and results in the past decade... and not just because the SECE was down one year. The only way to jump from nowhere to number one overnight is through questionable recruiting efforts, and Spurrier ain't going there.
As for RTR91's question (a legit one IMO), the answer is nobody knows. USC returns a sr qb along with arguably the #1 WR and #1 RB in the SEC next season, so there is hope. The fact that USC beat those 3 teams by a combined score of 91-44 suggest that there was more to it than just those programs being down, USC also played well and had a good football team.
Back to Clowney, Keeping kids like that in-state has been a real struggle for USC over the years. Spurrier has started a trend of keeping these kids at home, if he's able to land Clowney I think it sends a strong message to the rest of the SEC powers that they can no longer just waltz into SC and steal the top talent anytime they want (which has been the case in the past). Glimore, Holloman, Jeffery, Lattimore, and Clowney are all kids who likely go elsewhere in the past, so something is changing in Columbia IMO.