I don’t think this is all on Arch. A big part of the issue is how Sark is using him. Last year Arch was much more dangerous as a dual-threat QB through the first five games he had about 160 rushing yards and 5 rushing TDs. This year he’s around 100 yards with no rushing TDs. That’s a significant change in how defenses have to account for him.
Against a defense like Oklahoma that blitzes heavily, I thought Texas would use more QB movement, RPOs, zone read and designed runs to punish that aggression. Instead, Arch spent a lot of time being asked to sit in the pocket and process pressure, which is probably the weakest part of his game
When the offense keeps going three-and-out, the defense is right back on the field. Texas having stretches where they couldn’t sustain drives, their defense started wearing down combined with Arches two brutal fourth-quarter mistakes. I think the bigger question is whether Sark is tailoring the offense to what Arch does best right now or trying to force him into the quarterback he wants him to become. To me, defenses are not having to defend all of him. You would think that sark what design six 6 or eight purposeful carries, more movement of the pocket, more RPOs and fewer static obvious-passing situations and that would make the entire offense harder to defend.