I'll throw out another idea here. Belichick is Belichick because he plans so carefully. It's not enough just to have a good quarterback. He can win with receivers or with no receivers. He can win with spare parts on defense. He can win when he loses players to injury in situations where most teams would fold up and accept an 8-win season. Belichick is the only guy out there who knows what the word "dynasty" means.
He is not going to let this team go into any season without an answer to every question he can think of.
This may be the most important chart I've got.
Number of regular seasons with 10 or more wins, 2003-2013:
11: New England
10: Indianapolis
7: Green Bay
6: Baltimore, Philadelphia, Pittsburgh
5: Atlanta, Denver, New Orleans, Seattle
4: Carolina, Chicago, Cincinnati, Kansas City, New York Giants, San Diego
3: Dallas, Minnesota, New York Jets, San Francisco, Tennessee
2: Arizona, Houston, Jacksonville, Miami, Tampa Bay, Washington
1: Cleveland, Detroit, St. Louis
0: Buffalo, Oakland
Belichick doesn't rebuild. He plans. You can call this chart Brady/Manning/flotsam and jetsam if you like. But I would call it planning for every contingency.