@zens I could be entirely mistaken. Perhaps frequent archiving, frequently tested, would not eliminate the problem of ransomware, but it would mitigate the problem to something close to elimination.
Another possibly mistaken idea is to have one's software and data so in the public that there is no ability to own it. A page of HTML might be ransomed, but HTML itself cannot be. I'm sure there are many projects and business that could not operate this way.
@onan@zens I agree on archiving. Maybe using a COW filesystem and mirroring the snapshots to a different machine. Also add a tripwire: when many of your files change over a short period of time, notify sysadmin.