teach TA to have rare abilities only found in top flight runningbacks. This is basic logic… if Harvey created Tyler then why didn’t he create TA replicas with every RB on the roster that he coaches? It’s cause you can’t teach this abilities.
If a coach could simply teach how to become Michael Jordan, Patrick Mahomes, Tyreek Hill, Travis Kelce, Jose Altuve etc… then every pro would purchase the services of those magician coaches but since you can’t teach talent and abilities we will always see disparity as a result of varying levels of talent and ability.