"This means that cryptocurrencies are the only tool left for ransomware purveyors. So, if governments take meaningful action against Bitcoin and other cryptocurrencies, they should be able to disrupt this new ransomware plague and then eradicate it, as was seen with the spam Viagra industry."

This is the totally incorrect approach. Imagine banning Polaroids because they led to an explosive growth in underage pornography.

These exploits are happening not because of crypto but because of insecure systems that public, money making companies haven't invested in making secure.