I really don't think it is a stretch to postulate that the play had a significant effect on the psyche of our core players. Moreover, the aftermath was handled in the worst possible fashion by Bevell. What he did is pour gasoline on the fire. He essentially said the playcall was great and it was all Lockette and Wilson's fault. For a team that built itself on the identity of family, and on phrases such as "we all we got, we all we need", the response from the one of the coaching staff ran contrary to the values espoused upon the players by Pete Carroll.
What is even worse yet was Belichecks and Butler's response. They said that had been practicing against this very same play all week long. Belicheck also made note that it was easy to point out, because that play call was the ONLY play that the Seahawks use out of that formation on short yardage downs.
Over the years there has also seemed to be a kind hostility towards the offense by the players of the defense. A look of contempt that is saying "you're not pulling your weight". Even Sherman, in one of the losses this year talked about it being frustrating when you play your heart out, and have the offense no pull its weight. I think that by keeping Bevell after the playcall, and his handling of the incident that Pete Carroll's coaching philosophy lost a lot of its impact. Especially the bit about being "all in" and "always compete".
The players in recent years seem to have lost their edge. Many of them look like they are just going through the motions. Ever since that loss it has been clear that there was a disturbing paradigm switch.
