I don’t think that’s the case.
The last couple of years, defenseman have been putting up near 100 point seasons. Karlsson was the first in like what, 3 decades, to put up a 100 point season? That’s extremely rare nowadays and it’s being done now.
Orr, Bourque, Housley, Coffey, Lidstrom were all points leaders when they won their Norris. You can say there were *better* defensive players than them 1 for 1. But that’s the thing, those guys wouldn’t even come close to the above offensively.
Historically speaking, the Norris trophy was always more favourited towards point leaders. And majority of the Norris winners (with the exception of 2023 Karlsson who was IMO the worst defensive player to win it) can hold their own defensively. What seperates them from other defenseman is that they simply produce more which has a much more direct impact for the team. If you spend more time on the transition, can effectively hold onto the puck in the offensive zone, and maintain consistent possession, you will concede less goals. Currently, no one does this better than Makar, Hughes, Fox or Josi.
There will always be someone better than another defensively. In terms of determining who’s better than the other offensively, that’s easy. The higher scoring player and the one that does it frequently.