@HighEliteMajor Your assumptions about the complexity of the spread is not accurate at all, especially in regards to the OLine. Run blocking is always more difficult to execute than pass blocking is, always has been and always will be. The reason being is that in run blocking, the OLine has to have the strength to open up the running lane for that particular play which means the OLineman has to be stronger than the guy he is blocking.
In pass blocking, OLinemen don't even attempt to move down field because of the risk of an illegal man down field penalty. Because of that, in pass blocking the goal is to not give up ground which is always much easier than trying to gain ground. Even if you don't hold your ground, forcing the DLinemen to go outside and having to loop around to get to the QB gives the QB enough time to find his receiver.