my take and this based on a non athletic person, per se.
players have a different level of talent and yes that well of being an elite, once they reach it, differ per player. the 2nd level is and this is where a poster who played at a higher level competition would be happy to inject some of their knowledge here.
Toews, he played a vast amount of his games, playing on the first line may have taken a toll on his body. now i will support this with the knowledge that players who were elite, some 20+ yrs ago, when they hit a certain level, the skills start to diminish. which i attribute to Toews and in some extent Seabs. Seabs is different with his head / upper body injuries that he has received in his very good career.
this is, i guess more recognizable with the new sports medicine progress then it was back in the day . now comes that understanding and an org willing to embrace it, to understand it.
again i will always remember that great yrs, the SC yrs.