Changes in bitcoin are possible and happen. For example, if we want to have more divisibility, we have to change the protocol.
To allow more complex transactions, the protocol is going to be changed soon.
those kind of changes don't do any harm to my money,
yours would.
and i gave you a few examples how it can hurt me.
if i'm a non-techie person and want to "hoard" my coins offline, using BitBills for example, you want me to destroy them after X years (and import the BTCs to an online wallet), just to not lose my coins.
i bought those BitBills for a reason, i paid for those coins, it's up to me what todo with them.
no protocol-changes ever should change that, or at least should be on their own fork (maybe i would use that fork too, by choice, not forced to).
I've got it.
Instead of having to move them, you could just send the address some coins. All you'd have to do is send the minimum transaction to the address to keep it active, which would push back the demurrage date another 20 years. I think that would be good enough to demonstrate control of the wallet. and you wouldn't destroy the bitbills.