General Westmoreland Mutes Reveille Bugler
A directive from General William Westmoreland did away with morning reveille formations as part of military reforms in 1970. This probably led to the call of Reveille begin changed in the US Military from the call of a morning roll call formation to one for raising the colors.
Reference Army and Air Force manuals.
It’s interesting to note in the article that the Marines said they would not go along with the new reforms saying they would “tighten regulations. if anything.”