One has to keep in mind if a black out is because of a auxillery engine break down or because of a fire. If the aux engine breaks down a emergency generator kicks in automatically. That,s standard on all ships, not just paxer. However if a fire is involved it is a whole different story. The fire can/could have damaged the switch board of in the ECR (Engein Control Room) which could mean, even wenn the emergency generator functions properly it is still possible that the electricity produced can not be switched "on line".
All ships have for emergency communications 24V batteries, SAT-C / VHF / MHF etc is powered by that, and certain areas lighted. But all major stuff, like for example air-con is gone. Ventilation systems are mostly down as well as cooling pumps to a certain degree.
So it is not so easy to say,,ship is new,,how that can be. I really depends on the situation. Same as with airplanes as long the fly,all is fine. same here,as long all is function normal all is fine. we have to get used to the idea that one day 100,s if not 1000,s possibly die because of a fire (smoke inhalation is the major cause of death then) not because of the resulting flames but the smoke.
My wife often wanted to make a cruise,, I told her sail with me here. Those paxers are nothing else then massive floating coffins if it comes to the worst. Think about, 1000,s
of peoples, mostly never ever been on a ship, in average rather old, and rescue them. The Costa Concordia was in that matter a lucky case that she was laying on a rock, if she would have moved off that rock and capsized, TITANIC would/could have been overtaken in the death toll easily.