A snapshot and update won't magically make your collectibles' addresses safe.  Bitcoins would have to move to a new address under your scenario, which means collectibles would have to be peeled for their bitcoins to be moved to a new address.  This will cost fees and need to be done BEFORE quantum computers compromise the network, not after.  I don't think not worrying is an option you can have for much longer (they're saying 10 years) without losing all of your bitcoins.  I get that for Bitcoin moving forward it would not be an issue, as they can upgrade the hashing algorithm.  However, it would mark the first time that legacy Bitcoin addresses would become useless, which is a major concern in my opinion.  Then there is also the concern of "satoshi's coins" and what happens once they're stolen by quantum computing.  It's almost as if there's a massive reward available for anyone able to break the encryption.  I don't know if there's any way around the chaos that is coming our way from a technical standpoint regarding legacy addresses, but I do know that it is something currently not being taken seriously by collectors and makers.

Right now a quantum computer is as big as a gymnasium. The amount of heat they generate is the biggest problem. When they do get it all figured out. It wont be something we all have. There will be like 2 or 3 quantum computers on the planet. Definitely not worried about my coins being compromised. Like others have said. As quantum improves so will the blockchain technology.