I think admissions quotas appeal to those who take a Marxist approach to matters
@Fullofsurprises ; who see academics looking after their own through the admissions process. Quotas negate that. I accept the bona fides of academics; that for the most part they are genuinely trying to select the most able.
George Bernard Shaw intended his aphorism that "justice is like the doors of the Ritz Hotel, open to all" to be ironic. In the case of university admissions, some
@AllonsEnfants! believe it to be a simple statement of the truth.
I think any totally objective admissions system will be gamed by the sharp elbowed. My view is that quotas should be used to increase the size of the pool, not who is fished from the pool.
If you say A*BB is acceptable for admissions, then every Wykehamist with those grades will apply. If you say that A*BB will be acceptable for kids from Bash Street Comp only, then you might well get kids predicted to get A*BB applying from Bash Street Comp without being swamped by the mediocre of Winchester. You can then interview the comp kids alongside the Wykehamists with straight A* predictions. The corollary to this is that there is no point in giving everyone the same conditional offer,if that offer is out of reach for people identified as having the requisite ability.
I used the example of A*BB because i think this one of the evils of the UCAS process. The key to admission for any competitive course is a candidate's weakest subject and that is one of the advantages of the teaching at the best schools. They get people with only moderate talent good grades. "I'm sorry Mr Shakespeare, we can't admit you to our creative writing course with that E in geography. How can anyone who thinks Bohemia has a coastline possibly succeed in writing fiction? Rather than that second rate grammar school in Stratford, you should have attended Eton or even that new academy alongside Ye Mosse Bourne."