I believe you are correct. Not because they can't coach but there isn't much left to coach. Next year, I think we'll see the kickoff rules applied to punts - then it'll really be an uncoachable part of the game.
"Wedge-blocking, employed on 78 percent of kickoff returns last season, was eliminated, as was the 5-yard running start previously afforded to the coverage teams. Players were re-aligned so that only three members of the return team could be more than 15 yards from the restraining line, creating a punt-like environment of running with opponents rather than at them. And officials were instructed to rule the ball dead if it bounced in the end zone, an attempt to encourage players to stand down their blocks earlier."
"The memo reported that injuries on kickoffs have decreased, including zero concussions during the preseason, and noted that wedge blocks have been virtually jettisoned. Contact between blockers, meanwhile, has transferred from high-speed collisions at the back end to slower-speed interactions closer to midfield. Although there has been no final decision, it would require a significant reversal of those trends to prompt the elimination of the kickoff for next season."