It’s an interesting idea, though I hope it never happens for the following reason.

Silver has a stock to flow of about 20 - or 5% new stock every year. So it’s not going to play a huge role as a long term store of value, as you mention. More comparable to dollar bills.

So if it did happen, it’s a world where cash has been outlawed, and also dollars and other currencies are depreciating far faster than silver - enough to go back to this place. I kind of hope not, but you might say we’re already halfway there..