Unfortunately, without the pressure of earning your living and finding a better situation to do so, there is little reason for people to move teams. If you want to encourage movement; offer a way for teams to recover value from players lost to FA (so that the players leaving don't feel as bad making that decision) and lower the cap to force teams to make decisions in who to keep. It's really the only way to get people to leave the sub-communities they've likely become attached to.