All of the quality control analysts in CFB are getting titles now because they are allowed to coach on the field. I think Furman has as many as 5 QC last year that all had "assistant" titles.
Obviously Thacker is well beyond that in his career, and at the major schools I think they are just accumulating as much talent as they can and paying them and calling them Assistant ____ Coaches. Clemson just hired UNC WR coach and he is an "assistant" to their main position coach. It's the way of the new CFB world.