Why was Alain Vigneault relieved of his duties?

For starters, let The Maven say that for weeks I have been asking assorted Rangers fans whether they wanted A.V. back behind the Blueshirts bench in 2018-19.

About 75 percent asserted that he should be replaced — and for all the reasons you’ll find below.

General Manager Jeff Gorton will meet the media Monday morning and explain in detail why a coaching change is imperative and why A.V. was deemed N.G. at this point in time.

[Read Official Press Release]

Here are substantive reasons:

1. MISSED PLAYOFFS

Heading into the 2017-18 season, Vigneault had a lineup capable of making the playoffs. The Hockey News — The Game’s Bible — picked New York to reach the postseason. Ditto for many media types, including me. Finishing under .500 left the club far, far below expectations.

2. TEAM OVERHAUL

Since assuming managerial leadership, Gorton has been changing the franchise’s face on the fly. He has been dealing left and right, turning the Seventh Avenue Skaters into a younger, faster team. Inevitably, a coach whose non-playoff record this season was 34-39-9, with 77 points figured to fall into the Overhaul Basket, as he did.

Islanders 2, Rangers 1 Bill Pidto, Ron Duguay and Steve Valiquette look at what to expect from the Rangers heading into the offseason. Islanders 2, Rangers 1

3. NATURE OF THE BUSINESS

No matter how you shake it, winning coaches eventually lose their impact. Their message gets stale and fails to resonate in the room. Look at Joel Quenneville in Chicago; fortunate to still have a Chicago gig after a miserable season. Farther back, Hap Day won three straight Cups for Toronto (1947, 1948, 1949), the first time in NHL history any coach had done so and Day was gone as coach by 1950-51.

4. DECLINE OF DEFENSE

Whatever Alain’s game plan, it began suffering in the past two seasons. The backline’s performance alternated between disorganized and chaotic with no noticeable improvement this last time around. Time and again, pressure on goalie Henrik Lundqvist in particular — as well as his backups — was relentless and left The King ruling a castle without a moat.

Islanders 2, Rangers 1 Is Henrik Lundqvist still a top goalie in the NHL? Steve Valiquette thinks so and has a formula for the Blueshirts to follow in order to keep the franchise goalie strong next season. Islanders 2, Rangers 1

5. DEFIANCE?

The Rangers general staff made a momentous move early in the homestretch. In a candid declaration to fans that the club would be moving in a more youthful direction, it revolutionized the roster en route to an offseason of anticipated change galore. However manner Vigneault’s remarks may have been interpreted, it seemed evident that the coach disagreed. Having the mentor on a different page than management may not be the best way to run a hockey club.

[Read: What’s Next For the Rangers]

6. BOTTOM LINE

The Rangers wound up at the bottom of the Metropolitan Division. ‘Nuff said.

David Kaplan, who has followed the Blueshirts for years from Manhattan and now Israel where he lives, has studied the club from an analytics perspective. After learning of the coaching change, he wrote: “The reasons I have seen include, misuse of players, inability to adapt, refusal to accept statistical analysis, and, finally, his inability to accept creative young playmakers who invariably make mistakes.”

That’s one critic’s opinion among many on both sides of the issue.

Ironically, all of the above does not mean that A.V. is a coaching failure; far from it.

Leading the Rangers, he won 226 games. He took his team to a memorable Stanley Cup Final against Los Angeles. Given a few skinnier goal posts, his club might have won the mug. He orchestrated a trip to the Conference Final and captured a Presidents’ Trophy, not to mention six playoff series victories. No small feats. When a coach can boast 648 career wins, he has a legitimate hope that there’ll be an NHL owner looking for someone like an Alain Vigneault next season.

As for the next Blueshirts coach, the guessing actually began last fall when it appeared that A.V. was one loss away from getting the gate. He got the necessary win and kept his gig.

Since the club is going the youthful route, Denver University’s successful Jim Montgomery merits consideration while unemployed NHL types such as Darryl Sutter and Dave Tippett, among others, are looking for work.

Classy, insightful and an all-around good guy, Alain Vigneault will be missed, but the franchise comes first and foremost which is why a new coach eventually will be named; perhaps sooner rather than later.