Could it be "cronyism"?
Need help in finding a word (if it exists) that means to deliberately hire a less qualified or incompetent candidate for reasons of ensuring new candidates are not a challenge to higher levels. The meaning is similar to that of nepotism in which of course candidates are selected not by qualification but by whether they have family/friend links. These links would normally also guarantee loyalty and ensure the higher levels are not challenged in a similar way.
Could it be "cronyism"?
Nepotism and cronisym both suggest the applicant chosen was known personally to the employer, although this normally also means the applicant was not the best qualified.
I think the best phrase so far I have come up with is 'mediocracy protectionism'.
Some words that I have investigated which touch on the concept are:
the practice among those with power or influence of favouring relatives or friends, especially by giving them jobs.
cronyism or croneyism:
the appointment of friends and associates to positions of authority, without proper regard to their qualifications.
The Pitt Principle:
deliberately destroy, damage, or obstruct (something), especially for political or military advantage.
a person who acts obsequiously towards someone important in order to gain advantage.
a dominant class consisting of mediocre people, or a system in which mediocrity is rewarded
the theory or practice of shielding a country's domestic industries from foreign competition by taxing imports.
Antonyms (Opposite to):
There is no set word or phrase for this. I've worked in corporate Anerica for a number of years and I can't imagine any of the places I've worked doing this. The suggestion above is a good description, but ther is no word/phrase you can use that would have immediate understanding of the concept because the concept itself is so strange.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.
There is 'positive discrimination', but I think that usually works in favour of equally well-qualified people in racial (or other) minorities; it's odd that women, in the context of employment-seeking, are sometimes regarded as 'a minority', although I think they outnumber men by a percentage point or two.
There is also the word 'quotas'. In some contexts (often political) there must be a quota (of women candidates, say).