I agree 100%.
It's especially important in the NFL, but all through every level in football, right down to Junior High, the better the line, the better the team. There are a few exceptions here and there, but that's a general rule to build on.
Best example may be the ol' Redskins. Slow, heavy, white RB (Riggins) unstoppable behing the Hogs. Decent but not great QBs (Williams, Rypien) winning Superbowls.
Agree 100%, but it seems like in the NFL great offensive lines seem to be a product of the system and are built by coaching rather than high draft picks. Teams like Denver just plug in another player and keep going.
If a team's offensive line is performing poorly especially over a period of 3 or 4 years then the fault likely lies at the feet of the coaching staff.