That assumes that failed sales during an outage are lost forever, not merely delayed.
I've heard from various third-party developers that store downtimes (of reasonable lengths) tend to be followed by corresponding sales spikes, so that ultimately nothing is lost. I have no idea if that applies here, but it's reasonable to think it would at least partially.
I'd say that a sizeable part of App Store sales or downloads are impulsive purchases: i.e. you think you need something or are in the mood of playing some game and you can't resist hitting the button. If you can't make that impulsive purchase now, you tend to forget about it until you are in the right mood again. My take is that a very high amount of sales has been lost, not deferred.
I am willing to wager that the average sales is not uniform over the day/week. Now we are getting towards a full day, but I would hardly count the hours from 0130 to 0500 as downtime for lost sales.
I've heard from various third-party developers that store downtimes (of reasonable lengths) tend to be followed by corresponding sales spikes, so that ultimately nothing is lost. I have no idea if that applies here, but it's reasonable to think it would at least partially.