Why do you say that? Remove all of their career stats from the history books and league-wide scoring would still have been much higher in the 80s than today.
Adjusted goals is a very good stat and the fact that Gretzky and Lemieux played at the same time is only an extremely small part of the reason why leaguewide scoring fluctuates year to year. Copying this from another recent thread:
Average goals/team/gp in 88-89: 3.74
Average goals/team/gp in 88-89 if LAK and PIT played but were shut out in every single game: 3.66
Average goals/team/gp in 2000-01: 2.75
Average goals/team/gp in 2014-15 (Tavares' only 1st team All-Star selection): 2.66
There are probably more statistically rigorous ways to answer the same question but 1) you'd get a very similar result and 2) it involves a better database than HRef and I don't want to spend the time doing it ...
Gretzky and Lemieux had really incredible impacts on league scoring, far more than any other players in history. Over the course of an entire league season though with so many teams, so many players, and so many games one player is a drop in the bucket -- even if they're the best player of all time. The full story of why overall scoring levels have changed is a much larger (and very interesting!) one that involves a ton of different factors, none of which really have anything to do with one or two specific players being in the league.
Yes, but if you make such adjustments, Lemieux is ranked higher, isn't he? And Wayne may also be ranked higher.
Also, the formula for the adjusted goals is looking at the average number of goals after the goals of that player are removed from the calculation. This seems to penalize significantly a player who had, let us say, 163 assists in a season; the fact that he had so many assists makes his goals in that year worth much less.
Adjusted goals are not a perfect model, and there are many other ways of adjusting for this, which likely lead to a different ranking.
Here is a very simple comparison between two seasons, tell me what is the correct rate for goals conversion:
1986-87
Average goals per game (per team) :3.675
Highest scoring team: 4.65 G/G
Lowest Scoring team: 3.25 G/G
Top scorers: 62, 58, 54, 54, 52 (adjusted to 82 games: 64, 59, 55, 55, 53)
Top Assists: 121, 72, 70 , 64, 63, 63, 59 (adjusted to 82 games: 124, 74, 72, 66, 65, 60)
2024-25
Average goals per game (per team) : 3.08
Highest scoring team: 3.58 G/G
Lowest Scoring team: 2.48 G/G
Top scorers: 69, 57, 54, 51
Top Assists: 100, 100, 89, 75, 71
Now, if you remove Gretzky from 1986-87, there is no 60-goal scorer or 75-assist player.
In both years, there were exactly 17 40-goal scorers. There were much more 50 assits players in 24-25 than in 86-87.
So in which year is it easier to score?
These stats are saying that the depth players scored much more in the 86-87 than in 24-25, but the top players in 24-25 outperformed the top players in 86-87. Yet, the (i)logical conclusions is that we should use the much higher depth scoring in the 86-87 to conclude that the top players had it easier.
BTW: looking at these stats, I suspect that the top players actually played much less than 24-25 minutes many top players play today, which would explain these stats.
The reality is that it is much harder to adjust for era than people realize. And all the adjustment formulas I have seen are terrible.