‘Tis true, if you push on a wall for long enough, it will fall down, eventually
Not if you’re below the creep threshold, otherwise your mountains would have flattened out by now 🙂
OK lets sort/summarise this….
Chains do stretch elastically under ANY load, but return to normal length when unloaded.
Chain parts do not stretch plastically, permanent length changes are caused by wear at the inner plate/pin joint. So while the chain may change length over time the question of stretch becomes one of do we define stretch as a change of length of parts of the chain or a change of length of the item as a whole.
If you look on a half-link basis the chain does not stretch, if you look on a whole-link, or whole chain basis it does by way of wear.
The word stretch does not require deformation to be due to plastic or elastic material deformation?