The core issue: Who determines merit, ability, and position? The people who write the rules are the actual government, and governments secure their own power.

You touched on a really important point here: when humans are judging skill, it’s subjective and not really meritocratic.

One of my favorite psychology professors says that people really like the idea of meritocracy, when it’s actually present. He gives the example of sports, and how people aren’t bitter about a particular team winning, or that there’s big inequality between the players, and that the reason people are okay with that inequality is the presence of the playing field and the high speed cameras and whatnot means meritocracy is the actual basis for reward, not personality politics.

In business, government, etc it’s all people judging other people, and on an individual basis. A group of people evaluating is better, like star ratings for an uber driver are probably more trustable than performance evaluations from someone’s boss. The latter can be so heavily distorted by that one person’s judgment.

The ideal is using measurable performance as the measure of “merit”. Like when people run a marathon. As long as the course is visible to confirm nobody’s cheating, that marathon time is yours in a way your degree or your job or your salary isn’t.

It’s also why people are so in favor of free markets deciding resource allocation rather than people: the free market is at least a large crowdsourced combination of everyone’s needs, instead of just some mental image of those needs in the mind of a few committee memebers.