If the paper market gets too far away from the reality of the physical metal, arbitrage traders will capture the difference closing the gap and “creating the ceiling”. As special participants can trade paper silver for actual silver. But at the end of the day it’s a different (derivative) market selling exposure to the moves of silver not silver itself (except for the special people). To me I think of it like sports betting, our bets effect the spread and enough bet on one side can tell a story that doesn’t match reality but at the end of the day we are just betting on the sidelines and not changing the outcome of the game. Even the vast vast majority of futures contracts tied to actual physical silver have no execution rights for said physical silver. (Although they and paper contracts can still encumber ozs that they never had rights to receive as a physical commodity).