I'm interested on your take on your 5th point. Its quite a bold claim that has been disputed over in the development sub forum and here by some pretty bright minds. Why do you think its an impossible task? I think its difficult for a number of reasons including but not limited to the consumer issues that would come with bigger such a big change. As far as I know there are many different projects working on including quantum resistant algorithms into the existing infrastructure of Bitcoin and they are making good progress. The only issue with that is this would require a hard fork and there will be multiple different options to choose from. I would be interested in getting achows opinion on the matter but I'm afraid that discussion about quantum computers would quickly get buried.
Yes, I should've probably disclose in more details.
When we say "it is quantum safe signature" we imply "it is probably quantum safe signature" due to the fact that someone had already mentioned in this thread, we don't have a quantum computer yet. What we need here is a solution with an encryption variability to have the opportunity to transfer new keys for the analogues of old addresses after hard fork. If we won't have this feature we'll have to make multiple hard forks with every "new" quantum computer. Another reason is a performance decline because a lot of PQ sigs are "heavier". Everybody are waiting for NIST PQC results. Actually this is what one of our products is about and this is one point of the articles. So it is difficult as a one time task but if you do it several times it requires an architecture rebuilt to make it easy and reliable. Plus we're talking not only Bitcoin but any other blockchain.
So it is an issue.