Lopp’s proposal is the only one I know of on this topic that’s sort of concrete in when it’s saying to freeze coins, and every suggestion I have heard is prior to QC being able to do so (as the theft of Satoshis coins would be the obvious and huge first lost to the problem). But even in that context I still land on the “we don’t freeze coins” conclusion because who knows how many people might still be able to move coins and want to come back before any QC decides to go after their UTXOs, etc. I don’t think it is reasonable to assume any QC even after decades of being able to break one with a ton of energy or work, would be able to quickly or in a matter of moments, just break signatures wantonly. Which leaves a massive gap between “they spent 5 years breaking Satoshi’s coins” and “everyone else is immediately vulnerable” landscape.
In other, other words, I still think it is very likely that almost everyone save for the highest and most obvious balances would potentially still have years to move their own coins *after* Satoshi’s were already broken.