If it truly was North Korea or people they paid do you really think those they targeted would be safe anywhere? About any country can disappear someone, even outside their own country, and North Korea isn't beyond that, they may not be to the level of the US or Russia but I have read they had a fondness at one time for kidnapping Japanese nationals.
Sony should make some sort of TV-connected "console" to let people buy and download media over the internet. Waaaaait a second.
I know the movie studio and consumer electronics divisions aren't the same thing, but if they really wanted to get this video out I have to imagine that the Sony-umbrella companies are capable of working together.
My bet is they change course and still show it in theaters. Maybe not on the original launch date, and maybe not everywhere, but (caving to terrorists aside) they spent a pile of money on this and they want to make it back.
This has turned out to be a dead loss financially for Sony either way, and when you know you've lost the current game, it's time to start thinking about the next one. Being seen to capitulate like this marks Sony as an easy target. The next time some bunch of cybercriminals wants money and is thinking about targets for some blackmail scheme, who's going to be at the top of their list?