This some interesting data. Are your percentages based off of the real data or adjusted points?
I'll start with the bottom quote first. Basically, what I've found out is that while the raw numbers of goals, assists and points varies based on scoring levels and number of games played, the underlying G%/P% (and A%, though I don't actually calculate that, it's just inferred) does not change. If league average goals was somehow 500, say they played 162 games instead of 82 (and players had a similarly-high percentage of games played in both situations), the peak player-seasons are still going to garner points on somewhere between 40-50% of their team's goals. If that team in a league average of 250 scores exactly 250 goals, a P% of 40 means they'd have 100 points. In a league average of 500, they'd have 200 points. In a league average of 125, they'd have 50 points.
If you want a different comparable, the shortened 19-20 season is a perfect example. Because the season was shortened, they played 70 games, in a league average of 208, and you have a perfect comparable in the 62-63 season, where they also played 70 games in a league average of 208. Look at these player-seasons:
Rank | Name | Year | Team | Games | Goals | Assists | Points | Team GF | LA GF | % LA | G% | P% | VsX | Avg VsX |
2 | Andy Bathgate | 62-63 | NYR | 70 | 35 | 46 | 81 | 211 | 208 | 1.014 | 0.166 | 0.384 | 100 | 88.83 |
3 | Stan Mikita | 62-63 | CHI | 65 | 31 | 45 | 76 | 194 | 208 | 0.933 | 0.160 | 0.392 | 93.83 | 83.35 |
4 | Frank Mahovlich | 62-63 | TOR | 67 | 36 | 37 | 73 | 221 | 208 | 1.063 | 0.163 | 0.330 | 90.12 | 80.06 |
4 | Henri Richard | 62-63 | MTL | 67 | 23 | 50 | 73 | 225 | 208 | 1.082 | 0.102 | 0.324 | 90.12 | 80.06 |
16 | Dave Keon | 62-63 | TOR | 68 | 28 | 28 | 56 | 221 | 208 | 1.063 | 0.127 | 0.253 | 69.14 | 61.42 |
8 | Patrick Kane | 19-20 | CHI | 70 | 33 | 51 | 84 | 208 | 208 | 1.000 | 0.159 | 0.404 | 86.60 | 92.12 |
10 | Jack Eichel | 19-20 | BUF | 68 | 36 | 42 | 78 | 193 | 208 | 0.928 | 0.187 | 0.404 | 80.41 | 85.54 |
14 | Evgeni Malkin | 19-20 | PIT | 55 | 25 | 49 | 74 | 221 | 208 | 1.063 | 0.113 | 0.335 | 76.29 | 81.16 |
17 | JT Miller | 19-20 | VAN | 69 | 27 | 45 | 72 | 224 | 208 | 1.077 | 0.121 | 0.321 | 74.23 | 78.96 |
51 | Bryan Rust | 19-20 | PIT | 55 | 27 | 29 | 56 | 221 | 208 | 1.063 | 0.122 | 0.253 | 57.73 | 61.42 |
Compare Bathgate to Kane, Mikita to Eichel, Mahovlich to Malkin, Richard to Miller. Their teams scored just about the same amount of goals, and they had a similar P%, thus about the same number of points. Doesn't change from 1963 to 2020 (though we're a little unlucky that we have no exact matches of Team GF/Points in the top 20). The Keon/Rust comparison was the closest I found to exactly identical seasons, though obviously Rust played fewer games. Because everybody only played 70 games instead of 82, you don't have to adjust any sort of scoring. 35 goals and 46 assists in 62-63 are 35 goals and 46 assists in 19-20.
Since G%/P% is so static, when I place a player-season into a different scoring environment, I'm not really adjusting anything. Yes, the raw numbers are different, but you can also think of it as increasing or decreasing the number of games played. Hull's 59-60 was a 206 league average in 70 games played, which is a 241 league average playing 82 games, or a 294 league average playing 100 games, or 147 playing 50 games. He has 42 assists in the 206 league, he'd have 49 assists in the 241 league, 60 assists in the 294 league, and 30 assists in the 147 league. Whether he plays 50 or 70 or 82 or 100 games, his assists per game average is still 0.60. When scoring goes up without increasing the games played, that's when per game numbers start going up, and the same as when it goes down.
[Moving up to the Pominville, Roy, Bouchard versus Ovechkin, Hull assists quickly, I feel like you made an incomplete conclusion looking at those names. Sure, Pominville, Roy and Bouchard all had more assists than Hull would have, but they also all had more assists than a peak Ovechkin season. You concentrated more on the first aspect than the second one. Also, I'm using outlier and peak mostly cavalierly, and not being consistent in my usage of both words. Bouchard's assist number is not an outlier season, in terms of raw assists, it is an outlier season in terms of his career.]
The VsX argument is actually an interesting one, because I basically built my adjusting engine to do a different calculation for VsX. Instead of relying on yearly samples, what I did was input the league average from 05-06 through 18-19. [I basically built it during the pandemic, so that was the most recent full season. I could extend it further, but 15 years seems to be accurate enough.] So Hull's 59-60 season gets put into 05-06, converts to 229.94 team goals scored, 46.95 goals, 50.56 assists, and 97.51 points. With a VsX of 106 that year, his seasonal VsX is 91.99. Do that for 14 more years, average all 15 numbers, come out with an Average VsX of 89.70, compared to Hull's actual VsX of 101.25. If you refer back to the 62-63/19-20 table above, VsX is massively different for both seasons - it is 81 in 62-63 and 97 in 19-20. Average VsX thinks it should be just about 91, or just above the middle of those two extremes. That's why both Keon and Rust have the exact same Avg VsX - same number of points, same scoring level. They shouldn't be 12 points apart.
When you take best 7 of Avg VsX, Hull goes from 108.3 to 96.11, and Ovechkin goes from 98.4 to 100.7. It goes back to the 450 player-seasons versus 1800 player-seasons. VsX numbers were softer in the O6 era because 18 top-line forwards isn't enough of a sample to produce outlier seasons every year. If you look at the seasons closest to 100 in Average VsX, it's 07-08 Jarome Iginla, 24-25 Howie Morenz, 22-23 Pastrnak/Kucherov, 10-11 Corey Perry, 89-90 Mark Messier. I did an experiment where the sample I used for Average VsX was 53-54 through 66-67 (another 15 year sample), and the benchmark of 100 there was 07-08 Ilya Kovalchuk, 30-31 Joe Primeau, 02-03 Modano/Palffy, 36-37 Sweeney Schriner, 06-07 Ovechkin, and 62-63 Bathgate (as you see above Bathgate is 88.83, versus 99.86, or just about a 11 point gap). There were just over 150 player-seasons that exceeded 100, versus about 375 using the O6 VsX.