BYU, U, USU, SUU, WSU coaches all have a significatn RM settling in period. They would disagree with the "myth" claim..
My son will play on scholarship for one of those teams. He gets home in June this summer, they asked him to get back in shape in the fall, report in January so that he has a full year to recondition. He'll go to school part time in the fall, help coach his HS football team, workout with position technicians, and Stroshine. He avoids burning a year of eligibility while getting muscle, speed and explosiveness back, then get going with the team in January.
I would say coaches in Utah have the data/evidence and that's why thy bring guys back carefully. CB might not have the evidence but they do.