I like this guys approach to demonstrate effects of roller vs. elongation wear. That must have been some worn chain. LOL.

https://bike.bikegremlin.com/3370/ro...th-chainrings/

But yeah, I get it. Roller wear could effectively reduce the pitch of the chain as it disengages, but I am not sure whether this actually is what happens,.I think the forces on neighboring rollers as the come off the chain are in the same direction, so roller wear doesn't come into play.

EDITED to clarify.