Appreciate the comments, and it was so much easier to see in retrospect than while we were going through it. I kept hoping against hope each season that the D would somehow rediscover their LOB form, I mean, how could it just evaporate, never to return? Surely "defensive genius" Pete would find a way to bring back the boom. Yeah. That didn't work out. Then somebody pointed out Pete's habit of in-season draft trades, and how it was about propping up Pete's record at the expense of selling the team's draft picks for questionable returns and had the effect of bloating the salary cap with veterans. Then I realized how short-sighted of Pete, even narcissistic, that was. Only in hindsight could I see how utterly terrible Pete had been as a GM.
I have guesses about the firing, but it seems so hard for outsiders to really guess. My guess is that Bert Kolde or someone in his circles commissioned a study of Carroll and Schneider and the team's performance and trajectory, possibly by an outside panel of consultants, and supplied the report to Jody. Of course, that was a super-easy job, the consultants just browsed the Seahawks.net board for a couple days (or was it 10 minutes?), noted the recurring themes, did some stealth polls on the site (I suspect Jerhawk as the mole who posted the surveys for them) then copy and pasted the recurring themes and survey results into their report. ;-)
Then Jody, Bert, and the panel met, decided Schneider's performance was more than acceptable given the last two very good drafts, and then brought Schneider in to discuss Pete with them. The panel had given a "below average" and "potentially move on" rating to Pete. John shared the best objective viewpoint and data he could, which largely validated the panel's conclusions. The decision was made to move on from Pete and begin the search for a new HC. Then Pete was called in, told that there was a recommendation to move on from him, and given the floor to advocate for himself and why giving him two more years would be in the team's best interest. Pete expounded on his usual lame Pollyanna blather, how close the team was, they just needed to get over the hump, one more year and you'll see the difference, etc. Then the panel asked Pete how he was going to beat Shanahan and McVay, Pete responded with the same formless delusionally optimistic blather, "a couple players away", etc. The panel all rolled their eyes at Pete's schtick, Jody read the body language, informed Pete of the decision to move on, and asked John to lead the search. John insisted that Pete be retained with the title "advisor" since they had to pay him anyway, may as well get some work out of him here and there.
A broken clock is right twice a day, so that's my broken clock guess.