I think at least we need to be open at the idea that he was better than anyone now, in absolute, there is no reason for a better than Modano athlete to be born at any time and to have chosen hockey.
Very hard to tell either too, I would agree that we cannot know for sure that when Modano was a clear top 5 center in the league that the 4 better than him were not also better than any of Morenz competition.
Modano from 1993-94 to 2002-03 was 10th in points-per-game, with career-best point finishes of: 8, 9, 10.
Among Canadian center, Modano during that time would have been quite high
Second to Lindros in +/-, third in points, third in ppg among the 500 games or more played, second in goals.
Third in playoff points, 4th in playoff ppg
Among Canadians is top 10 finish look more like 4, 6, 6.
I do agree the car analogy can be clunky here, the claim he is that Morenz was a better athlete or not (i.e. would it have been likely than training in the 90s he would be better than malkin or not), while a Corrola is just better than a Model T at being a car.
Maybe too extreme in the other way, but chess player is a good analogy I feel like where it is so easy to imagine anyone in the Top 200 today would destroy Fisher in chess, well old Kasparov of today would destroy the 1988 version, while the 1988 version was a much better chess player than the old one has your brain slow down and endurance-collagen, etc.. as well, there is only a knowledge difference not a skills at chess one.
It is possible that Bobby Fisher had the highest peak of any chess player ever, no one suggest that putting him in a time machine that he would day 1 be in the top 1000, he would get crushed by people that know a lot of is game by heart and mountain of knowledge since his time and we cannot know how much is talent would transfert to modern day chess which is a bit of a different game.
Heavyweight boxing is an other one where how attractive, popular, large the talent pool (when you could be 5f10-200 pound and compete), talent pool among war veteran and other hard life growing up type, it is easy to see it is up and down flow in talents and not just getting better and better, even if in a time machine way maybe the latest one win it (but that a rare sport where it is really maybe not, there is not much equipment change, rule and so on).