This highlights what BB's issue was at the end here and what's still plaguing him in North Carolina. The well of good football minds he works well with has dried up, both in the front office and the coaching staff. Look at all the good coaches we had over the years. All the good scouts/front office personnel. Sure, some of them failed when they left but they were all qualified and functioned well in their roles here. We had a legit "brain trust" around BB.
Into his late 60s and early 70s, BB simply lost the ability to identify and develop good coaching/front office people around him. And it's not even just about how good people are at their jobs. You can have two geniuses but if they don't work well together they're going to produce ****. Once it started crossing generations and having to incorporate new ideas and new ways of thinking BB simply couldn't foster a good culture in the organization anymore. He didn't have the adaptability or the interpersonal skills for it.
Everyone makes it about Brady leaving - he only played 3 more years after he left and the roster had deteriorated already. The damage was already done. With all the benefit of hindsight and seeing what went on behind the scenes, it seems like at some point in the mid to late 2010s BB could no longer lead a healthy organization and it was all downhill from there. The fact that they still had Brady and all the other great players they added when they were a good organization masked it because they kept winning but once that dried up and they were left with the players and situation that the dysfunctional drafts and offseasons produced, it was over. Brady staying 3 more years wouldn't have fixed it.
20 years of unparalleled success should be celebrated vs. hand wringing over why it wasn't 25 or 30. But if you have to ask what could have been done for that, they probably would have had to fire BB mid 2010s even amidst annual SB appearances and brought in a whole new regime that hit the ground running and was great. A total crapshoot that could have just as easily (and probably more likely) gone bad than good since most front office/coaching regimes flop.