As to the Yin/Yang perspective on increased/decreased morale for the defense vs. offense, that's got a resonance to it for me. I've watched, probably six times by now, the ULTRA excellent television series, Three Kingdoms (2010) which I highly recomment to anyone looking for a true epic tale based on one of the Four Classics of Chinese Literature. In it, they frequently put things in Ying/Yang terms "The Riverlands are easy to defend, but difficult to attack from" or the like, there's probably two dozen lines like that scattered throughout the series that are intentionally demonstrating inverse relationships at key moments. Love it when my favorite pastimes intersect like that :-)
Think that Yin/Yang Offense/Defense morale issue might have played some part in Seattle's O-line woes? Also FA linemen, especially those who think they could get another contract AFTER one with Seattle, don't exactly want to be on the wrong side of a sacks highlight reel when they sit down for an eight figure negoriation. Kinda tough to defend such when you're arguing over an extra million dollars of guaranteed money.