Ok, be warned, I'm about to lay down some serious Belichick smack. Im sorry but without Tom, Bill is just your average sub 500 coach and everyone around the NFL knows that. Without the biggest draft steal ever, he'd probably be on his 8th coaching job now, most of them coordinator positions.
Pre Brady, Belichick earned fame by taking the Browns to a 11-5 record and a divisional playoff loss. Fun fact, they had the number one defense that year under DC Nick Saben who left after the season. Five years at Cleveland and one at NE pre Tom produced a 41-55 record with the one said playoff trip.
Enter Toms second year in 2001 and low and behold theyre winning Super Bolws. Nineteen years for Tom in NE produced 17 playoff trips, six SB rings, three more SB trips resulting in losses, four AFC championship losses, two divisional losses, and two wild card losses. Oh ya, and one of the two years they missed the playoffs, Tom was injured all year. The other was his third in the league. NE made the SB in over half of Tom's healthy seasons.
Tom leaves and what happens? 29-38 and one PO appearance in four years resulting in a wild card loss and out a job now coaching in college.
Nineteen years with Tom: 76% 17POA 6SBW
Ten years w/o Tom: 43% 2POA 0SB
On a side note, how did Tom affect TB's success? In the three years prior to his arrival, 17-31 for a 35%. That includes SB winning coach Bruce Arians, who Tampa brought out of retirement, going 7-9 the year before Tom. Tom shows up and SB, 32-18 in three years and three PO appearances. Since his retirement, 27-24.
Sometimes you have great coaches and sometimes you have coaches with great players. In Belichicks case, he had the GOAT.