Parcells brought legitimacy to the franchise. Whether it was mostly just sizzle or actually steak is up for debate - that is, was he really that great, or was it mostly Belichick and personnel mainly responsible for the Giants and Patriots success? He certainly was an above average coach and at the time believed to be the best franchise builder/turnaround man in the league. The individual success of Belichick and Parcells’s mediocre results without Belichick have certainly called for a re-evaluation of Parcells, who has gone from all-time great to all-time good by general reputation. But no matter what, the man had a great personality and swagger, and he was a major influence on Belichick’s coaching/management.
I have to say, though, that I still recall the article from 2000 which was a survey of NFL people who put the Patriots as dead last in the league when it comes to likelihood of winning a Super Bowl in the next decade. This is not an exaggeration, and while the link no longer works, many is remember this actual article, and frankly it was accurate that in 2000 the Patriots has an abysmal outlook. So, I think Parcells should be given credit for what he did, but he shouldn’t “eat into” any credit that Belichick gets.
Belichick identified which veterans were worth keeping and rebuilt much of the roster. It’s not like Parcells had just left; like any team, the Patriots had a handful of good professional players among the 53. But then again, many of these “Parcells” players would be virtually forgotten, or at least much less esteemed, had it not been for Belichick building a dynasty. Belichick has proven with the 2010s that, whether it’s a team he drafted alone, or a situation he came into, he is the mastermind talent evaluator/ economics genius who will find the right players.