I have become of the opinion that whole thing was more Deuce than Tomlin. It may have been all Deuce. He's the only one who has said it out loud. Hear me out.
Tomlin resigns suddenly. I know about the rumors. But maybe after another playoff loss he goes to Art and says, "Hey, we gotta strip this down and rebuild it right because what we are doing isn't working." Art gives him the line about not wanting to waste a year and that he thinks they are close. Tomlin goes home, sleeps on it and decides he doesn't want more of the same and resigns. While not as fun as banging a bartender and getting her pregnant, it's plausible.