Ransomware is about money, not "warfare."
If they are asking for a ransom and actually provide the recovery code when paid, then it can't be about harming the nation.
They started out going after retailers and other small businesses, looking for smaller payouts. They were honing their ransomware and going after companies that had very weak, or no, network security or backups.
Now, they are going after highly visible targets. They've learned that the publicity of being hacked costs their victims more than the hack itself. The more high profile the company, the more likely they are to get paid.
This is not likely to stop anytime soon -- not as long as the criminals are able to extort millions out of one victim.