One other important point is that the very term "root cause" is extremely harmful in that it presumes a primary failure and already seeds the idea of one bad actor and, by proxy, blame. Systems today are too complex to blame upon one or two things - we operate in a very complicated, "complected" world both in our software and in many organizations.

While there are always technical causes for larger technical failures, I've seen far too many times RCA post-mortems performed that result in witch hunts instead of a solemn contemplation of how things could be better done by everyone. Such an RCA may ignore that a normally careful engineer was overworked by managers, never is lack of relevant monitoring and testing due to budget cuts cited, and you'll certainly never see "teams X and Y collaborated too much" as a reason for failure in these places. Because in a typical workplace, the company's values and culture are never related to a failure. You can't objectively measure how bad or how good a culture is either. Why make it part of post mortems when you don't think it's a failure?