If there was a backup available, we could recover - however in my previous post I assumed that backup copies would also be included as nodes which would be destroyed. Assuming a backup did survive though, this would lead to an interesting issue where we would have to take that backup as gospel, however without any independent verification how would we know that it was accurate. Even if multiple backups survived, collusion between the backup holders could result in the opportunity for fraud. We would lose the decentralised nature of bitcoin up until that point.

Even with the torrent file available, what good would it be without any seeders? Presumably all of the seeders copies were destroyed also?