The REAL reason TGW ended??

Does it seem to anyone that the real reason for the end of TGW and the transition to a new series was just to ditch J.M.? Much of the TGW cast has joined on the new show, the Kings are also involved. We all know that there was drama on set with JM and AP. Plus, I read that JM was willing to sign on for another season of TGW (though she wanted to ditch CBS broadcast network - which ultimately happened). Furthermore they wrote her character off the air --not as our hero-- but as a raging bitch who screwed everyone over. The ending was literally a slap on the face to the star! If CBS, the producers, and the star were all willing to continue, why was it cancelled... just to start anew as a facsimile, minus one key element?

I think there's so much more to the story.