It doesn't really matter. The point is the offense isn't able to routinely do things Sark thinks it can. From practice, or something.
The players aren't necessarily affirmatively bad, but for whatever reasons, just not performing. And it's not like they utterly cannot run the offense, they just miss it by . . . this much. The pass is off. The route is a little off. A missed block. Drops.
The glaring exception being the OL. I'll say it again, last year's OL just wasn't all that, despite the draft picks. The offense was good enough overall that it seemed like kind of a nitpick, but its lack of push in the run game kept our offense under wraps.
Of course, now, it's a glaring, massive defect that probably drives everything else wrong with the offense: Arch struggling, not establishing with the WR, and obviously the never-quite-gets-going run game.
Even the penalties, which seem most disastrously to center around an OL that is more than half-likely to get bitched on any given play. They're so nervous they jump, and then hold when they do get bitched; if they manage to engage a rusher at all.