The Chinese rulers realized they had a problem where incompetent rich kids got promoted to important government jobs. This caused the government and therefore society to function poorly. As a result of this, many people died unnecessarily.
To combat this, the Chinese government instituted very hard entrance exams that promoted competent applicants regardless of rich parents.
https://www.cambridge.org/core/journals/journal-of-asian-stu...
The 722-222BC in the article you linked to is the "wrong period". That period was a time where Chinese states transitioned from feudalism to empire, and the clan-based aristocracy was replaced by a class of educated and scholars due to societal change (which needed lots of literate administrators, and not so much nepotism). The typical path for a person who aspired to work in government is to apply to be an "employee" (very loose translation of 門客) of a prominent minister, and rise up the ranks by impressing their bosses. It was also common for rulers of the time to hold meetings with intellectuals, who then tried to sell the rulers on the latest ideology/methods to run a country -- if the sales pitch worked, they'd have the job of implementing those policies. In general there were no exams, although one would assume to become an "employee" they'd test your skills in some way, but it was not systematized at all.
Between 222BC and 6th century AD, the educated/scholar class gradually consolidated into a handful of prominent families who tended to monopolize high government posts. During the Jin dynasty (266–420AD) people generally believed one's virtues/abilities were tied to their birth and family status more than anything else. This was a time when prominent families monopolized government power and systematically rejected outsiders from holding important positions, even if they proved their abilities.
The imperial exam system introduced in the Sui/Tang dynasties gradually reversed this trend by allowing commoners to participate in the government exams, though it must be noted in the Tang dynasty exams the circumstances of the candidates were taken into account (family background, social ties, subjective opinion of the examiners, etc.), so it wasn't purely based on the paper exam results.
The exams were gradually systematized in the later dynasties, ultimately ending in the "Eight-legged essay", which was famous for its rigidity in form. It provided a great opportunity for intelligent aspirants from a underprivileged background since everyone took the exam on an equal footing, but it kind of sucked the soul out of learning the classics.
Big reason why the FAANGs get dysfunctional too. You either have to be very, very, very, fast to fire, almost arbitrarily (Amazon) or you end up with a bunch of people who feel safe enough to be trying to advance.
The "rich kids" w/o anything but college and FAANG were taught Being Visible and Discussing Things and Writing Papers is what "hard work" is, so you end up with a bunch of people building ivory towers to their own intellect (i.e. endless bikeshedding and arguing and design docs and asking for design docs) and afraid of anyone around them who looks like they are.
It's something a rich kid would come up with if they'd never done real work, and were incapable of recognizing it, but they'd seen body-building, and they decided that's what everyone should demonstrate as the fundamentals, and you can't get muscles like that without being good at work.
And of course, besides the flawed theory, everyone cheated at the metric.
But other rich kids had more time and money for the non-work metrics-hitting, so the rich kid was happy they were getting "culture fit".