Maybe most people have figured out that there is no use in paying because the program doesn't know who has paid.
Paying a bunch of criminals is no solution. If you pay them once, you will give them incentive to continue doing so. Plus you don't know if your files will really be decrypted after paying. Only solution is to either professionally have the systems 'cleaned', or they need to be wiped out and a back up being installed. I am quite happy that the number of paid ransom is severely lacking if you take the size of this attack into consideration.
You do not trust the criminal? There is a solution - In the future, malware will have smart contracts. You can be sure that your files will be decrypted once you pay the ransom. The only way to transact with an untrustworthy person.