So it looks like Seadream was very successful in their "Ruby Princess" plan -- quickly get the potentially infected passengers off the ship and scattered onto planes to home where contact tracing would be minimal to none. 2 crew tested positive as/after the passengers were departing, anyone thing it's really likely that *zero* additional passengers were infected? I can't find any more recent information -- if there was followup with all of the passengers and all had been negative a few days after returning home *that* would have been reported by the cruise line, so it's telling that there was no further reporting.
Cruising really can't be restarted unless or until the lines, the authorities at ports, and even the passengers themselves are willing to take actual precautions and more importantly be a partner in dealing with infections that occur. That includes no-whining quarantines on or off ship when needed, participating in followup confirmations, and honest reporting of the results.