Are you just trying not to understand it? It's pretty simple.
1. LSU interviewed Shoop in 2015, after his first year at PSU. After an initial interview, he declined to continue talking with LSU and returned to PSU. And in fact, LSU did not offer him the job. Instead, Shoop got a raise from PSU.
2. AFTER the 2015 season, Chavis took off and LSU hired Dave Aranda, not Bob Shoop, and they did it 1.5 weeks before Shoop came to Tennessee. Therefore, they wanted and got Aranda, not Shoop.
And ftr, at the time of and even before Shoop's hiring, I was absolutely thrilled. When LSU hired Aranda I recall being relieved and thinking "whatever, Shoop's the guy we want". So much for that thought.