The period from 1995 to 2004 in the NHL is sometimes referred to as the "Dead Puck Era" in reference to the decreased scoring environment. In this period, the average goals per game decreased and the average save percentage went up. Some of this effect may have been from improved goaltending play, but a lot of it was due to better defensive play, relaxed rules on clutching and grabbing, increased goalie equipment size, and other factors.
How much did this era help the goalies who played in it? Quite a bit, as it became easier to post high save percentages and low GAA numbers. One of the major beneficiaries, of course, was Martin Brodeur. It is easy to look at his career numbers (even his save percentage numbers), and wonder how anyone could claim that several other goalies could have easily matched his performance in New Jersey. Yet that's what I'm going to try to demonstrate right now.
Roberto Luongo, probably the best goalie in the NHL, is in his eighth season in the league. I wanted to look at the goalies who entered the league between Brodeur and Luongo, i.e. roughly somewhere between 1993 and 2000, to see how playing in that particular era impacted their save statistics. For a fairer comparison, I took only their first 8 seasons, starting with the first year they played more than 1000 minutes. Both are somewhat arbitrary cutoffs, but I needed to set the yardsticks somewhere, and for most goalies 8 seasons includes a few prime years and goes up to around 29 or 30 years old. For goalies in their 8th season like Luongo, I included this year's stats. Here are the save percentage results:
1. Roberto Luongo, .919
2. Manny Fernandez, .913
2. Tomas Vokoun, .913
4. Martin Brodeur, .912
4. Mike Dunham, .912
6. Evgeni Nabokov, .911
6. Guy Hebert, .911
6. Martin Biron, .911
6. Olaf Kolzig, .911
10. Jose Theodore, .910
10. Dwayne Roloson, .910
(There are a few others who didn't make the list because they only had 7 seasons played but would also have ranked ahead of Brodeur, including Manny Legace (.916), J.S. Giguere (.916), Marty Turco (.914), and even David Aebischer (.912).)
What conclusions can we draw from this list? Simply that the effect of the era they played in was much stronger than the individual goalie effect. The difference between #2 and #10 on this list is very slight, just .003 in save percentage (1 goal every 333 shots), and that is over an 8 season span. The only guy who distinguishes himself is Luongo. Brodeur is mid-pack, despite playing on the best teams (especially defensively) of any goalie on the list. It is interesting to see him tied with Mike Dunham, who began his career as Brodeur's backup in New Jersey.
Some of the goalies played fewer minutes, because they spent times as backups, which means one or two good seasons could be skewing their results. Those who played over 20,000 minutes in their first 8 seasons include Luongo, Vokoun, Brodeur, Nabokov, Hebert, Kolzig, and Theodore. So there is a good deal of evidence that except for Luongo they were all pretty close to each other in performance over their first 350+ games in the NHL.
Olaf Kolzig and Martin Brodeur had almost the same playing time and the same save statistics (29,432 minutes and .911 for Kolzig, 30,055 and .912 for Brodeur). Pretty much the only difference between the two of them was the strength of their teams. Olaf Kolzig is certainly one of the league's most underrated goalies - I would argue that over their careers, there is little to differentiate him from Martin Brodeur. The only difference between them is quantity, but not quality.
Martin Brodeur has had a very good career, but this has been primarily because of his great defensive teams and his longevity, durability, and favourable deployment by his team (i.e. his coach sending him out to the net virtually every game). For the majority of his career, he has stopped the puck just as well as the other decent goalies in the league, even before considering how relatively easy his shots were. He just came into the league at the right time and on the right team to put up massive career numbers. The low-scoring era Brodeur played in is another major reason for his impressive career statistics, but relatively speaking they are far from great. Brodeur's save percentages are often invoked in arguments involving some of the slightly older goalies like Roy, Belfour, and Joseph, but once you factor in era there isn't much difference at all (except for Roy, who ranks well ahead of Brodeur).
Just as an aside, there was one goalie that did not make the list because his first qualifying season came in 1991-92, but I thought I'd just mention him for comparison's sake: Dominik Hasek. Despite playing in three relatively high-scoring seasons to start his career, in his first 8 seasons Hasek posted a .926 save percentage, which outclasses everybody on the above list. In the Dead Puck Era, the low-scoring environment made it look like everyone was good at stopping the puck, but the record shows that nobody was even close to Hasek.