This thought is only in theory. Without Gretz and Mario doing their thing it wouldn’t lead to the extensive training and discipline of a player like McDavid today. If he was born in the same era he likely wouldn’t be the same player. However if you took him from today and transported him back in time he would most likely be better than both guys if that makes sense.
I think this is just plain silly. Scoring is way up this year, and scoring in several years in the 80s only had 1 or 2 50 goal scorers. There’s going to be like 10x that this year. You have seen lots of anomaly years over the history of the game, like 1992-93 which is an outrageous scoring outburst, likely due to a combination of skilled european imports, rules changes (TV timeouts, etc), and skill dilution (expansion teams). If you go back to the 70’s a lot of what is happening now is fairly comparable to years that Esposito/Orr dominated the scoring race. There are ebbs and flows, and players who change the game, and rules changes up and down. Reffing has a major impact on scoring year to year. 05-06 saw a HUGE uptick in power plays being called and saw players like Ovie and Crosby catapulted to some of their highest numbers ever in their rookie seasons. They got better over time but their production was no better in their prime than it was as rookies.
In like 2000 people were already calling it the dead puck era, but you were literally a couple years removed from some of the highest scoring years in history. 1995-96 saw some numbers that approached the best seasons ever. The same players were playing. Lemieux was there in the 80s 90s and 00’s and even though he was hobbled he was still scoring point per game against the new superstars who are still playing today.
If you just look at transference, even guys like Gretzky in their retirement years against players who were going through training and development regimens similar to todays athletes, they were still posting point per game as senior citizens.
The idea that players could jump back and dominate the field the way Gretzky did is asinine. People attribute Gretzky’s numbers to the era effect when he had like 100 more points than anyone else in the league Some years. Its not close.