Leadership is one of the most misused words regarding pro sports. Participants are paid to do a job just like everybody else that works for a living and reports to a supervisor.
In your company, do you need a leader, other than the head of the department to achieve goals? If goals are not met, do they blame that on a lack of leadership?
Teams do not need leaders and most don't have them, just what some perceive to be leaders because they do some stupid dance like Lewis or a sillyass speech like Brees. Do the players really need that? That's all for show, it's all BS.
Take leadership out of the equation and replace that with accountability. That's what separates the real teams from the pretenders. Belichick isn't the leader of that team and neither is Brady, he is discharging his duties and doing his job as the QB. Belichick is the one that holds everyone accountable and will bench a DB for the playoffs or kick the QB's business buddy out of the locker room because there is one boss and everyone knows who he is. And everyone knows what is expected, "do your job" and that is defined by Belichick.
Know how McVay held himself accountable? He called it like it was, he got outcoached and there's not a player on his team that will hold that against him. And he will be able to hold them accountable because of the standard of accountability he has set.
The Cowboys do not have any accountability because the owner does not hold the GM accountable who doesn't hold the HC accountable who is not allowed to hold the players accountable. Garrett doesn't even hold himself accountable and won't admit mistakes. It is a team with a set up for excusing not achieving goals.
We throw around the word "leader" for Michael Irvin but was he not the one that held players accountable during the games? We all know Jimmy was the head of accountability but that was after games. Irvin was a leader through example because of how he practiced but when he knew a player wasn't "doing his job", he was in his face and asking him for his best. Accountability isn't yelling at a player or threatening him, it is setting the standard for what is expected of him and not letting him off the hook when he fails to deliver.
The NFL isn't what it used to be with guys like Lombardi, Landry, Grant, Noll or Jimmy or Parcells. Big guaranteed money and the cap restraints ran Johnson and Parcells out of the game, their way would not work anymore. Players didn't fear them and fear was a big part of how those men coached back then, the fear of losing your job or being singled out in team meetings or the fear of disappointing your coach because those men all shared one belief, without accountability, we will fail.
However, there is one that still demands accountability and people wonder why he still just keeps winning. No player in the NFL has the fear of failure so ingrained in them as a NE Patriot and if they don't have it coming in, they acquire that fast or they're not there.