The team lost its 2 starting CBs and had Troy Brown and Earthwind Moreland out there, they won a SB and played great defense.
They made a SB with Julian Edelman playing corner. Ok, that wasn’t a great defensive team, but they kept it competitive in the playoffs. That same team had a dominant offense with its 4th string center playing at some points.
They won a SB because of an INT by a UDFA, and made the above SB with Edelman as cornerback because of a pass breakup by a mid season practice squad signee.
Obviously those teams had talent elsewhere that this current team doesn’t have. But Belichick was able to coach up players and scheme them into positions to succeed. It’s up to the new coaching staff to do the same, and so far I haven’t seen anyone exceeding expectations here, only missing expectations.