Okay, so, generally, I think you can look at three things with respect to a GM's track record:
A) Drafting and Developing
B) Free Agency
C) Trades and Waivers
For the most part, some GMs are going to be better than others at these catagories. David Poile is a trade whizz and is a very good drafter, but isn't always as effective at free agency. So when evaluating Bergevin, Chiarelli, and Holland, we have to look at those three things logically. I'm only going to evaluate Bergevin here (this takes too much time lol)
Let's assume that for a good draft, you have to find either one superstar, two other NHLers with at least one of them being a top nine forward/top four defenseman, or three NHLers (measured by games played or expected (if still a prospect)
We'll evaluate trades, waivers, and free agency adds on a case by case basis.
Marc Bergevin, GM of the Montreal Canadiens, hired May 2, 2012
Catagory A: Drafting and Developing
2012: Alex Galchenyuk, Charles Hudon - Grading: while Galchenyuk could have been better, he's a clear top 6 winger, at worst, so this is a PASS
2013: Michael McCarron, Jacob De La Rose, Artturi Lehkonen, Sven Andrighetto - Grading: Although some of these guys are fringe, Lehkonen and Andrighetto have been very solid players. PASS
2014: Nikita Scherbak - Grading: one bottom four defenseman isn't good enough. FAIL
2015: Noah Juulsen - Grading: see above. FAIL
2016: Mikhail Sergachev, Victor Mete - Grading: Sergachev looks like a stud, Mete looks like a top four d-man of the future. PASS
2017: Too early to really project
Drafting and developing record: 3-2. However, it's important to note that in the past three years, it's been 1-2.
Catagory B: Free Agency
2012 GOOD: Carey Price second contract, Lars Eller extension
2012 BAD: Brandon Prust contract
2013: Nothing, really?
2014 GOOD: PK Subban Contract
2014 BAD: Nothing, really
2015 GOOD: Galchenyuk Bridge, Alex Semin 1-year deal
2015 BAD: Nothing, really
2016 GOOD: Philip Danault extension, Alex Radulov signing, Al Montoya signing
2016 BAD: Andrew Shaw 6-year contract
2017 GOOD: Joe Morrow contract, Alex Galchenuyuk extension, Ales Hemsky contract
2017 BAD: Carey Price extension, Karl Alzner signing, letting Radulov and Markov leave
Good years: 2014, 2015, 2016
Bad Years: 2012, 2017
Record: 3-2-1. Past three years, 2-1-0
Catagory C: Trades and Waivers
Michael Ryder + 3rd Round Pick <=> Erik Cole - Grading: Meh
Thomas Vanek + 5th Round Pick <=> Sebastian Colleberg + 2nd Round Pick - Grading: Win
PA Parenteau + 5th Round Pick <=> Daniel Briere - Grading: Loss
Sergei Gonchar <=> Travis Moen - Grading: Meh
Jeff Petry <=> 2nd Round PIck, 4th Round Pick - Grading: Win
Zach Kassian + 5th Round Pick <=> Brandon Prust - Grading: Meh
Mark Barbario waived and lost - Grading: Loss
Andrew Shaw <=> 2 2nd Round PIcks - Grading: Meh (although one of those did turn into Alex DeBrincat)
Shea Weber <=> PK Subban - Grading: Terrible
Jordie Benn <=> Greg Pateryn, 4th Round PIck - Grading: Win
Andres Martinsen <=> Sven Andrighetto - Grading: Loss
Dwight King <=> 4th Round PIck - Grading: Loss
Jonathan Drouin <=> Mikael Sergachev - Grading: Meh
3rd Round Pick <=> Nathan Beaulieu - Grading: Loss
David Schlemko <=> 5th Round Pick - Grading: Win
Mark Streit waiver - Grading: Loss
Record: 4-6-5 (plus the PK trade......)
So I think that Bergevin has done most of his damage in recent years, where his ideals for a winning philosophy don't seem to line up with the fans and the rest of the league.
However, BECAUSE most of his moves that seem damaging have no fully played out, I think waiting for the end of the season (or at least post-trade deadline, when he can no longer make moves), is the earliest you can fire him, especially since Montreal is currently occupying a playoff spot.
Conclusion: While Bergevin's track record has earned him a hot seat, with his team having some success, he probably won't be fired until the end of the year, at best.