The third Bellichick coordinator in two years to leave the Patriots organisation and become a head coach is Eric Mangini. He will be coaching the hapless New York Jets next year. Once again, the Pats are left with no coordinators.
As much as the salary cap, the way the draft is structured, and free agency prevent dynasties, I think the coaching system does so even more. If you're team is winning, other teams, that are desperate for quality coaches and executives, will come running to raid your organisation.
At least there wasn't any bad blood and no Dan Shaughnessey article with leaked material and no Patriots press conference to "react" to the loss of a member of the team.