Kyrie is extremely athletic.
As a result he doesn't take as much punishment at IT did.
I don’t think kyrie takes less punishment because of his athleticism. And I wouldn't say that kyrie is a better pure athletic either.
Basically, their games are different. IT seeks out contact (a la harden), which is why he gets to the line so much. He’s great at it actually. Kyrie, on the other hand, avoids contact.