Even on the cooped up cruise ship there was nothing close to full infection or super high mortality.
About 60% of those infected are reported as not recovered yet, even all this time later.
You certainly do have a point, but it is rather more limited than it might appear at first glance.
Itll be an interesting study, especially considering that as noted above the ship procedures were set up to deal with outbreaks of various diseases and are generally successful. It could be a lot of infection, or it could be surprisingly little when considering the actual conditions and events.
I heard an interview with one of the passengers this morning. He caught it, but his wife did not.