An effective running game can help an o line considerably.
I didnt say he was the cause of everything all the time. But he for certain was responsible for some dumb playcalling, not running the ball, relying far too much on thr pass, which, combined with inexperienced coaching on the o line put too much pressure on the group.
The OC runs the offense. He oversees that side of the ball.
Bith Waldron and Grubb are too concerned with making names for themselves as offensive masterminds to just call a balanced, nuanced game. - well Grubb has yet to show he can, while Waldron... well, he is out of work.
And Seattle's o line problems over the years didnt always stem from the same place. Sometimes it was talent. Sometimes it was coaching. Sometimes it was a QB who held the ball too long and sometimes it was all 3.
Context is important.