Calvin has said on multiple occasions and repeated this year "I want to retire as a Lion. I want to win as a Lion."
I believe him. He may still retire - everyone from Stafford on down said he is serious about contemplating it. He has said he will decide before FA so the team has adequate time to remedy their needs before the draft & TC.
I think his net worth number is probably higher than $30M. He lives pretty simply. He's very articulate & quote bright, but his desires are simple.
Johnson is a Christian. He has a tattoo of the crucifixion of Jesus on his left arm and a Christian cross on his right arm. He's part of a weekly Bible study group with other Lions players. He is funding a film called Real Love. The film is "a coming-of-age story about a girl trying to stay true to her virginity and her religion" and "... a message [Johnson] wants to get out there."
I don't think he is angling for a trade or being cut. He won't hang around to compile numbers. If he doesn't feel like he can still play at an elite level, if he has concerns about health or pain management, or if he's just fed up with losing, he'll walk. He won't look back.
That's just MHO, my take. He's a different kind of cat. He is in the world but not of the world. He doesn't view this through the same prism many of you are using (maximizing return, searching for a ring.)