[gfodor]

Often, but not always. When people generalize, it's an equal error to conjecture that the premise for the generalization is always false in the other direction. Lack of skill/experience is just a nicer way of saying incompetence, and sometimes this is a proximate cause, and sometimes this is actually a root cause, in cases where the person was a genuine bad actor who fooled others into thinking they were qualified for the position.

Now of course there are many times where this is used as a crutch to blame system problems, but I've found a trend towards the idea that it's never due to lack of skill/experience on the part of an individual, and always due to some other root cause. That seems equally incorrect, and good judgement about the cause should be agnostic to how one feels about the idea of saying an individual failed at their jobs (which usually isn't a pleasant feeling for most.)

On the upside, one should actually expect people to fail at their jobs occasionally within certain boundaries, in order for them to grow. So failures to due to 'incompetence' (not negligence) should be often accepted and blameless, given they should be happening occasionally if you are pushing people past their limits. The best way to ensure someone doesn't make large categories of mistakes is to let them make one with a small blast radius, and having them take responsibility for addressing the failure and remediations. (This isn't at odds with blamelessness -- most ethical people will accept responsibility for their failures and correcting them, if they are able to fail in an open, respectful environment)