The question is whether kids want to go to a RG and will take any uni and any course, just to get to one, or if they have a specific course and/or location in mind.
Some courses at some RG uni are extremely competitive. Top notch GCSEs and Hugh predictions for A Level will be needed for those. It is daft to pretend that people with a string of 5s and 6s have equal chances to those with all 9s for the highly competitive courses at the very top places such a s Oxbridge, or LSE or Durham.
However, there will be other courses which are less competitive which will give offers and places to people with much lower grades within the RG.
Question is, do you go for a course and a location you might not be so keen on, simply to say you went to RG uni, if your grades would allow you to do a course you'd love, but at a non RG?
Actually, lots of people would advise this - so do archaeology instead of History at a RG - saying this will open more doors than a History degree from a lower ranked uni.
It has to be a personal choice though. And I think everyone knows that in reality, when courses are over-subscribed, Unis have to decide who to offer to and who not to. Predicted grades at A Level are important, but bearing in mind there is so much over-predicting, GCSEs are important too. Not surprisingly, GCSEs are the best predictor of A Level preformance that Unis have to rely on, so they aren't totally disregarded and all GCSE profiles are not equal. Someone with a lower GCSE profile can access a RG uni but they will have to be more careful and choice of course and which ones to have a realistic chance.