Thanks for the link.
I think Lopp's proposal is crazy and should be rejected. Only 5 years (since the implementation of a post quantum scheme) to migrate addresses in a mandatory fashion to addresses with enormous signatures? That will lead to high block congestion which will be even worse than the threat by quantum computers. I will repeat it 1000 times more if it's necessary: everybody can now protect his coins simply never re-using addresses. The short-exposition attack is very far away.
And all coins that are existing, in my opinion, should be considered in circulation. And thus it should always be "priced in" that they can be sold at any time. This includes Satoshi's coins. Lopp seems not even to consider that once the bit old stashes like Satoshi's coins are sold, the Satoshi coin FUD will cease for all time.
If Bitcoin dips because a hacker steals all of Satoshis Bitcoins, then let it dip. It will recover.
PQC should be introduced, but completely in a voluntary manner. Tadge Dryja's approach until now is the most interesting one for me.
The proposal has one good argument that I have not considered before. If you have a working quantum computer that can compromise addresses that have been reused, the best course of action is to not do anything and continue to farm private keys. A silent attack. Once you have a very large number of cracked keys, then you can inflict massive damage all at once and take as much loot as possible. Other than that, the timings of the proposal are quite radical and there is no way that we can accommodate such a signature scheme without increases in block size.