Did ISU kill another promising coaching career?
No Campbell did it to himself.
Campbell was the one that didn't think he needed to replace Joe Houston as Special Teams coach following 2018 season. Houston went to Alabama and then Patriots where he is currently. Not having a ST coach has coast us a ton of games 2019 to present.
Campbell also didn't replace other quality assistants that left:
Alex Golesh was the Recruiting Coordinator/ TE coach, now OC at Tenn.
Jim Hofher was Passing Game Coordinator through 2017 and was replaced by Joel Gordon (disaster). Hofher is currently the Director of Advance Scouting at LSU.
Not to mention look at the Stadium, Crowd support and the facilities. Jon Heacock hasn't had a problem plugging in new talent to keep the D rolling. Why have the Offense (this yr) and Special Teams (since 2019) been in a complete tail spin?