It's not about justice or fairness; it's about results
I think a workable definition of merit is:
having demonstrated an ability or accomplishment that is related to the decision at hand, typically hiring, firing, and promotion. In other words, merit is using a person’s past results in a specific field to attempt to predict the likelihood that they will show similar results in a related field. In practice, this means using job experience, educational credentials, and test results for hiring, firing and promotion decisions.
A person can have a great deal of merit in one field and very little in most other fields. In practice, this is usually the case.
As you mentioned, the word has been somewhat conflated with the term “virtue” to imply that a person with merit is a more virtuous person than one with less merit. This meaning of merit implies a moral judgment about an individual.
I do not use merit in that sense. I would argue that merit is highly specialized to a specific domain, so that a person with a great deal of merit in one domain is very unlikely to have merit in other domains.
Is meritocracy rule by the deserving? Rule by the talented seems closer. This new elite believes they are deserving, does any elite not? SAT-measurable talent really does make better engineers or doctors. The best judges or politicians are wise and know the people, these talents that do not show on the tests. I'm not sure how to achieve it, but the notion IQ has no connection to wisdom or virtue could use reviving.
I have only started the essay, but I had to stop and shout aloud YES at this: "the belief that our relative worth (rather than our pragmatic utility) is a function of our aptitude." That I think is the question: how can we value people as people, human beings, without judging by IQ and resultant affluence? Christianity used to do this because each person was in the image of God . . . but now? Or MLK on "character instead of color" . . . but now how do we value people as brothers and sisters in humanity whether trash haulers or CEOs. And then the problems with not only hardworking trash haulers but the undeserving poor. It is a mess, so now I read the rest of the essay in hope.
If you are interested in this topic of merit, you might also be interested in reading my article on the subject: