Cui malo?
I was
puzzled because the use of Bitcoin eliminates big money as the motive for the WannaCry extortion.
Simpler answer: When mafias and governments use extortion, they aren't after money. They're seeking total obedience. In this case the direct 'victims' are losing some time and a little money, but they aren't seriously damaged. Who is seriously damaged by WannaCry? MICROSOFT.
No real mystery. MS is not
nice by any means, but it has remained relatively independent from Deepstate control. Apple and Google and Amazon and Tesla are enthusiastic Deepstate helpers. MS has tried to stay out of the loop. Now its reputation has been seriously damaged by Deepstate's extortion, and it will have to pay ransom in the form of obedience.