Earlier quoted context omitted.
I'm not a cryptocurrency advocate but as arberx points out in another comment this is avoiding the real problem. The problem isn't cryptocurrency or ransomware. The root cause is what needs to be fixed: Software publishers and software owners are to blame for insecure systems. Software development is like the wild west with absolutely no accountability. This need to change.
There is no evidence at all that computer science and information technology actually knows how to solve the underlying security problems without forcing untenable compromises on the economy. We can produce secure software, but only at a level of expense and time that would preclude most commercial software development.
Besides, software could absolutely be made much safer without destroying the economy. We all know that the systems that get hit are often a mess a twelve year old could "hack" by using specific search engines or kiddy scripts. Laws punishing those that run software with known vulnerabilities that end up causing society problems like these ransomware attacks do should have been made decades ago.