Like in the cases of US courts defining obscenity or fair use, there isn't necessarily a set of metrics which can be used to perfectly taxonomize something.
Imagine I sent a manuscript to a publishing house and they rejected it for being bad. I wouldn't expect they got to that conclusion by comparing it to a set of metrics, I would assume they have people in authority whose judgement is the decider on whether something is "good" or "bad".
The original comment was regarding employees currently being judged via metrics bringing up whether certain jobs can or cannot be judged using metrics is pointless.
Your analogy only works when applied to the hiring stage, as that is when the publishing house decides to work with you. If the publisher accepted your manuscript, assigned you an editor, gave you a target publish date, and gave you advance and then suddenly booted you and said “your work isn’t good” you’d have some questions, and rightly so.
This sort of thing happens all the time? Many manuscripts and screenplays are stillborn. Movies make it halfway through production before the plug is pulled. Software projects fail left and right, with millions of dollars spent (sometimes billions!)
Human endeavors sometimes fail to live up to expectations.
Imagine I sent a manuscript to a publishing house and they rejected it for being bad. I wouldn't expect they got to that conclusion by comparing it to a set of metrics, I would assume they have people in authority whose judgement is the decider on whether something is "good" or "bad".