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.
That would work too, but without saving space, people have still to maintain the chain from that ancient block where the address first appeared in an output.
I suppose you're right, but one step at a time. this would be the most amenable option for now.