Fair point in a way. But that's not always the case - luck plays a part. I mean, who played tougher than Howe and Messier? Both played forever. Ray Bourque played as robust as Bobby Orr and still went out on top, late in his career. Shanahan was a monster, so was Sundin. Some players are simply fortunate enough to get the breaks and some are plagued. In the case of Mario, you're talking about cancer at a young age. I mean, how unfortunate is that?
Barring cancer and a horrific back ailment, I think it is feasible to say Mario could have eclipsed 215, especially in 92-93, when he scored at the same PPG pace as Gretzky when he scored 215. Remove the physical and mental anguish of cancer, the time off, and it makes perfect sense that Mario scores about 220 that season... and that's being fairly conservative.
Orr was a different animal, especially since the training and advances in medicine were not on par in the 70's. However, I don't think it's outrageous to suggest he could've played, say, 15 seasons, without his knees bailing on him.
True, all hypothetical. And, again, this is making a case for them, not discrediting Gretz. Like the person above said, how does anyone discredit Wayne Gretzky? It's impossible.
I guess I look at it this simply...
Wayne Gretzky is a 10/10. So he can never be "overrated." However, some people take issue that Gretzky is a 10/10 and Lemieux is an 8/10 or Orr is an 8.5/10. To me, this is about making the case that Lemieux was a 9.8/10 and Orr was a 10/10. It has nothing to do with reducing Gretzky to a 9/10, etc.