This was a fine thing to say at the time Texas hired Sark, but that's an extremely outdated take at this point. The best thing about the team the last two years have been the defense, talent acquisition, and culture. If anything, Sark is showing that his primary value is running the program. His play calling and the offense as a whole is not what has been carrying this program to new heights. The offense's performance, especially against top 10 teams, is what held the team back from winning a title this year. Sark's #1 trait right now is absolutely his ability to be a CEO/run the program.
Sark doesn't need to be calling plays in order for his offensive system to be part of the reason he's a great HC. Sark can still have the team run his offense, script the first 15 plays etc. without being the play caller. Play calling is overrated. Very few people are so brilliant or terrible at it that it makes a big difference. Sark is somewhere in the middle, but he could also find someone who's about on par with him or possibly better at play calling. If he does that, it could free him up to focus on game management, in-game adjustments and better overall execution, and that could be a step forward for the program.