I think Drew's eventual departure was a given even absent what happened in 2001. Would have been a lot tougher sell, though. My point wasn't that, but rather that winning a championship in 2001 (not to mention with as Bill himself dubbed it "that team") bought Belichick and Kraft time to build on their relationship. Not indefinite time, but a couple of seasons in which to establish what the system could deliver over the long haul.
9-7 coming off a SB in what was then a competitive division didn't bother me. I was still trying to imagine what they could ever do to top the Cinderella season. But then even I took pause when he cut Lawyer. But over time, and reading Patriots Reign while basking in the glow of the championship that proved this was no fluke, I came to understand and appreciate the rationale. Player wasn't producing, player was satisfied with one ring, player was no longer all in and his influence and therefore future presence in the clubhouse was potentially problematic. And the second ring brought the man and the system several more seasons with which to operate with impunity.
Then back to back should have brought him unquestioned for life status IMHO, although in some quarters it seemed to have almost the opposite effect. An expanding fanbase and media became ever more demanding. And when we didn't win the media looked for excuses to criticize. For them spygate couldn't have come at a better time. They thought they had him by the short hairs...until his team went undefeated in it's wake... As consolation they got to revel in the SB loss, and then figured they hit the trifecta when Brady went down in the first quarter of the following season leaving his arrogance exposed via the butt of backup jokes that was Matt Cassel...
Only the system came through. It always will. It won't always win it all, but then who or what ever has?? What it will do is remain competitive. And because of what happened in 2001, 2003 and 2004 - that's really all it rationally has to do here. In places like Tennessee and Philly (and a score of others) they don't have that luxury. Which is why despite what Mike pointed out relative to longevity Fisher and Reid have both been on the hot seat at times in the very recent past. And they could be again in the not so distant future. Fisher's been saddled with the enigma that is Vince Young, reportedly by an owner who wanted to trump his former Texas rival with the selection... Reid has his hands full with the ongoing drama that is McNabb's up and down career in Philly, a lot of disgruntled veterans (and increasingly impatient fans) who bought in for a time and have little to show for it - not to mention the weight of his own ongoing personal tragedies to deal with.
Whether performance, drama or entertainment is your goal though, it's a great time to be a fan of the NEP. Has been for almost a decade now and I see no end in sight. And at the end of the day that is what Robert was looking for when he hired BB. The ability to maintain consistent relevance and competitiveness for the forseeable future. It's really not much different than what Irsay and Rooney were looking for although both had to hang on by their fingernails to ultimately reap just one ring out of Dungy and Cowher. The system in Pittsburgh has outlived Cowher, it reamins to be seen if it will outlive Dungy in Indy. But I don't forsee us having to gauge whether or not it can outlive Bill (or Tommy) here for several more seasons at least. Because we still have both for at least that length of time, and we could have Belichick for substantially longer. He doesn't seem to burn out in the effort as is the case with so many of his peers. But again, that may be the effect of having already acquired a fist full of rings to bolster the courage of his convictions. He doesn't waste much time or energy dealing with his critics, and the existence of doubters and the whiners rolls off him like water off a duck. He has nothing left to prove to them, and any things that remain to prove to himself seem to be best achieved right where he is, aligned with a like minded ownership whose long range goals are maintaining competitive consistency - from which anything is possible.