You know full well that academic discrimination is not what I'm talking about.
Its social discrimination.
I realise you think you're the only person who had thought about this, but strangely, a lot of us have, over many years.
Assume, and I'm not sure I think this is true, but arguendo, that there is some reified general intelligence that (a) predicts academic ability and (b) can be directly measured. This is the "let's pretend Cyril Burt wasn't a lying charlatan" position. That would mean that we could compare on this scale, which we may as well call g, two eighteen year olds, one of whom had been educated at Eton, the other of whom had been raised by wolves in the manner of Romulus and Remus. Suppose we determine that on our measure of intelligence, the latter is "more intelligent". How much more "intelligent" would they need to be in order to have a better chance of success in an MBChB programme than the former?
My answer is "they're disproportionate likely to fail, given realistic assumptions". Because the best predictor of success in exams is success in exams, and the idea that universities can fix in 66 weeks of teaching (in the case of the typical 3 year level 6 qualification) a deficit which has occurred over the 14 preceding years is farcical. Or, more crucially, can fix in the 22 weeks of the first year those self-same 14 years, such that the student passes the first year exams. BTECs provide Level 3 qualifications for people who can't take exams, but when they arrive in an environment where passing exams is the sine qua non of progression, they fail.
Universities cannot provide a crash course in the cultural capital, drawn in the widest sense, that people who have already succeeded in education have. Apart from anything else, universities aren't staffed by trained teachers and the methods of teaching and assessment are aimed clearly and centrally at people who have a track record of being taught, and arrive with the associated soft and hard skills. Your local redbrick's engineering department doesn't ask for A Level Maths and A Level Physics at Grade A just as a selection criterion, a quest for something correlated with g, they ask for them because on day 1 of the course you will need to use the skills and knowledge, and on day 2 you will have to learn more, building on them.
So what do you want us to do? Lower the entry requirements? Lower achieved entry grades are the single best predictor of failure, which is why Oxford and Cambridge have the lowest non-completion rates, by far. Yes, I'm aware it isn't that simple, because those grades are in turn proxies for other thing; that's rather my point, I think.
The solution that's creeping towards reality is foundation years, and they are now integrated for funding (you can get SLC funded as they are notionally Level 6 courses) and for progression (if you do a foundation year, you only need to progress into the first year, rather than gain competitive admission, so the bar is much lower).
But I suggest that before we all stand on the barricades with a chorus of "Can you hear the people sing?" building in your chest that you look at the completion rates both of foundation years, and (agreed, we only have one cohort to go on) degrees undertaken by foundation year students. Neither looks great, I'm afraid, and the people gaining for foundation years are often people with good A Levels in subjects X, Y and Z who want to do a degree which requires X', Y', Z'. In other news, those 60% of OU humanities students who already have a degree in something else do rather better than the remainder of the cohort who don't.
What else do you want us to do? Lower first year progression requirements as if that is even possible? Reduce degree content? What?
Making universities responsible for the ills of the education system, and society more widely, is confusing the tail with the dog. Yes, it's appalling that some children receive sub-standard education in schools (although I'd take some convincing that's entirely the schools' fault) and it's tragic that some children are very badly supported by their parents. But claiming that we can fix this, either by messing about with admission processes or by messing about with admission criteria, is just magical thinking. It's hard. A lot of us in universities are very keen to fix it, and don't spend all day raining empty sherry bottles down on the heads of the poor. If we had a solution, we'd implement it.