It's been a strength, but it's been trending downward over the past few years. If players are struggling to perform, it still falls on the OL coach. He's the one identifying and recruiting the players, right? So if we aren't recruiting good players, it's on him. If the players are good players, but are struggling to perform consistently on the field, it's his job to either coach then up or find a way to have them maximize their potential.
And when the same playcall results in radically different performance from the OL, I don't think you can blame the play calling.