Very often when a group of people are involved in some sort of underhanded behavior that involves joint actions by the members of the group - - in legalese, that is a conspiracy - - the group tends to come apart once an investigation begins. Members of the group begin to look out for self-interest and not group-interest. In this case, hanging all of this around Gregg Williams' neck was the "cut-and-run" strategy in the group.
It did not work - obviously - but it did succeed in one aspect. It showed Gregg Williams just how much cover others in his profession would afford him when the chips were down. Now, if Williams ever wants to have his suspension lifted, he needs to cooperate with the NFL in other investigations.
Translation: Williams needs to spill what he knows about what goes on/went on eslewhere.
Sean Payton, Mickey Loomis and Joe Vitt gave Williams reason to look out for his self-interest only when Commish Goodell comes to talk to talk to him the next time.