It's not about the physicality of the game.
Actually, it is. The physicality of the game made it harder to score and also is part of what made his usage rate so crazy.
Michael Jordan played 40 minutes a game and shot 27 shots a game. Would he shoot more today than he did back then? Would his 4th highest usage rate in the last 50 years somehow have been higher?
The point is, that with the game being less physical, it makes it easier to score. So, his shots and usage rate wouldn't have to be higher for him to produce more points.
People tend to talk about how physical the game was back then compared to today. But the bigger impact to today's game and why teams went away from straight isolation was the league allowing zone defenses. This fundamentally changed the game. This change alone would have forced Jordan to change his game. I'm sure he would have because he was an incredible player.
The zone defenses are why he likely wouldn't be able to average 40 on a contending team. Not a reason he couldn't do it.
But the notion that he would just tear apart today's game is simply naive and requires Dorian's assumption that the players 30 years were all just better players which is laughable.
What's laughable is to assume that a player like MJ wouldn't be at least as dominant now as was then. It assumes that he wouldn't take advantage of the advances in training, etc. that are available today and weren't back then.
Dorians premise that MJ could average 40 and still win as many titles as he did back then is wrong, but his premise that MJ could average 40, isn't.