There's a perception, perhaps flawed, that what determines the consensus is dormant wallet holders. This is not entirely flawed, because large holders do move the market value of bitcoin by selling the forks for bitcoin, and thus, play key role by being in the position to determine which fork remains the most valuable.
Interesting perspective. I think it has some truth in it, but only if you count holders which actually
could sell their coins at some fork, and it's not clear if this applies to Satoshi.
One could see it this way: If Satoshi has lost access to his coins (for whatever reason) then he would of course not longer be in that "consensus-relevant" holder category. If an post-quantum cryptography feature was added, we could probably witness if Satoshi is still present (=has access to the coins) because he probably would move the coins eventually if he has still access, even if the feature was optional.
If he doesn't move the coins, which I think has 80%+ likelihood at this point (because Satoshi of course knows that he can make the coins more quantum safe already by transferring them to "modern" addresses), and the quantum threat becomes real, then there are two possibilities for the fate of these coins: one, that a large part is hacked by a single group, and the other one, that most of the coins are distributed relatively evenly by several hacker groups. Only in the first case there would be really an incidence for consensus, and I consider it relatively unlikely; I think while some entity could have a first mover advantage with QCs, technology tends to spread rapidly (and there are several companies active in QC research), And as the first "quantum hackers" would probably take years to hack a single address, it is likely that when the first few addresses were hacked, other groups would have already joined that race.
Of course there could be the idea that Satoshi's coins are a kind of "insurance against bad development decisions", i.e. if for example a big group of holders are pushing for censorship features, Satoshi could magically appear and sell his coins on the "censorship fork". However also this is only the case if he is still able to access the coins, and as written above, the likelihood seems to be quite low because I'd expect him to move his coins out of the vulnerable P2PK UTXOs.
There's also the possibility that Satoshi is holding back his coins
deleiberatelydeliberately to not cause market disruptions. There are however possible strategies for him to prevent that, such a signing a message with one of his addresses with a message like "I'm Satoshi, and I will move my coins in the next weeks, but they will not be sold, only moved to a safer UTXO." Or "I'm an early miner" instead of "I'm Satoshi" if he want to preserve his identity.
tl;dr: I think the probability that quantum hacks have incidence on consensus (outside of side effects by market disruptions) is quite low probably.
@ABCbits: Thanks for the context, I vaguely remember that part of the blog post. But I think this isn't that important. What I think is, to say it bluntly, that Lopp and those agreeing with him are simply greedy and want to contract the supply even more, for Bitcoin to moon even faster. We don't know if (most) lost coins are really lost, and thus we don't know if there was a donation. So if the coins return to circulation we also can't say that this was a theft.