I honestly believe that this is an exception. Most people aren't going to be repeat offenders if proper blameless post-mortems/root cause analysis are performed. It will get to the roots of what actually caused it, and that can provide for a training opportunity.

Incompetence is generally caused by a lack of training, and carelessness is driven by culture. Yes, there really are cases where an individual is a problem, and potentially even needs fired. But most of the time it's the organization and its culture, policies, etc. that are truly at fault.

I think to an high degree it depends on whether the individuals could realistically prevent new instances given resources (e.g. access, head count, number of other high priority tasks, etc.)