Play, coach or observe a program with a great coach and a poor coach, and you'll realize the difference between a great coach and coaching staff and a sorry coach and coaching staff.
I have not coached on the high school, college or pro level, but I have been an assistant coach in community football. The first year my son played, the team sucked. The coaches played favoritism with the kids and put them in positions not based on ability but based on daddy money. We won one game. The next year we got a coach who met with the parents and said, "I don't play daddy ball. I put the best players at the position they're fit for. And I don't lose many games." I rolled my eyes, but then I realized what he did to back up his boast. He chose the fastest player and put him at quarterback. A lot of dads were hot because they wanted their boys to be quarterback, running back, receivers. But our new coach didn't care. He also installed a spread offense before any teams in the league were running spread offenses and made sure our boys played defense against spread offenses because he knew that was going to be the wave of the future (most of our kids were so freaking prepared going into middle and high school, it was unreal). Then he would study video of other teams. For the five years my son played with him, we won two championships, including an undefeated season, and only lost one game in any season.
Then when my son got to middle school, we had a talented team but an awful coach. We finished with a 4-6 record. The next year, we got a new coaching staff, a staff that knew where to put players and in what positions. We played some of the same teams we lost to the previous year and dusted them. We finished with a 10-0 record.
Then in high school, my son's senior year. None of the kids on our team, particularly our defense, had major SEC, ACC, PAC-10, etc. offers. Yet we shut down every team we played in our state, forced 26 interceptions, and gave up an average 10 points per game and limited the top ranked team in the State Championship that average 40 points per game to seven points. Many of the teams we played had guys go on to Power 5 programs, including Clemson, Georgia, Auburn, Alabama, etc. and we shut a lot of these guys down. What was our secret? We had EXCELLENT coaching and an excellent program. My son told me that our defense coordinator was a mastermind. He had the knowledge to examine tape and devise a game plan to takeout the opponent's best player.
Now that my son is playing college ball, he knows the difference between good coaching and bad coaching and, unfortunately, he says the coaching he received in high school is better than the coaching he receives in college.
Yes, players have to make plays. But coaches establish the program, plan and preparation for games. How did the Cowboys make the jump from Year One to Year Four to be a dominant team so fast? Talent AND coaching. Why were the Cowboys great on offense, defense and special teams during the 90s? Because Jimmy Johnson preached efficiency in all three areas. How did the Patriots build a dynasty over two decades without many superstars? COACHING. How did the Cowboys with Quincy Carter as quarterback reach the playoffs? COACHING.
Coaching is critical. If coaching isn't necessary or that important and let's change the game, let GMs and owners pick the players and let them coach themselves. It's not an either/or talent/players or coaching. It's both. But never underestimate the importance of the coaching to a winning team.