It seems to me like chainrings and cassettes wear slower than the chain. As long as your drivetrain is all equally worn out, you can get a ton of useful service life from the three parts without causing extra wear on one part versus another .
My e bike is either being thrashed, climbing hills, hauling groceries or any combination of the three, along with being regularly subjected to conditions which are downright horrifying for the drivetrain. Rain.. mud, lots of sand, etc. I do try my best to keep the drivetrain clean or at least properly oiled, but id expected the wear I got after just 1400km to be on the extreme side .