I don't think there has been a dramatic change this year though over the past couple of decades there has been a direction of travel with entry to top UK Universities becoming steadily more difficult perhaps reflecting both access initiatives and increasing demand from strong overseas students. Equally private schools will have seen some of their strongest students look elsewhere for tertiary education. London especially is so international that many parents will look at global opportunities.
Eight years ago when DS was applying for economics he was told to apply for the top four mathematical courses and be happy to get one, with the fall back of a gap year and reapplication. He was a strong applicant (5 A levels with four predicted at A*, and the equivalent of an AS in a MFL), but so were a lot of others. You needed to apply to all four as all are competitive and it is not possible to predict which one might take you.
In the event he was rejected by Warwick, UCL and Cambridge but got an LSE offer. A class mate got Cambridge not LSE. I don't really understand the earlier poster who says that her DS was not expected to get Cambridge but was disappointed not to get LSE. They have the same applicants and are both very oversubscribed, but select in different ways. Cambridge interview, LSE relies on grades and PS and like strong mathematicians.
DD then applied for medicine with 5 A levels and marginally better predictions and it was equally tough. She was apparently the first for a decade to get a Bristol offer from a school that sent 20-30 to study medicine each year.
I think what may have happened is that trends that very selective academic schools (state or private) have been aware of for a while have become more obvious. Strong students who might previously been predicted an Oxbridge place have been looking at Durham, LSE, Imperial, Warwick etc, and discovered that these are not easy either.
Does it matter? Not a huge amount, I don't think. From observation the more confident students fared better with Oxbridge selection process/interviews. . Very few of DS' friendship group got places, but as clever, intellectually curious, students with good study skills, have done exceptionally well elsewhere, with several now taking PhDs. (Oddly many they knew who went to Oxbridge seem to have headed for the city - perhaps that's where confidence gets you.)
If a University will get a student to where they want to get to, that is enough. Very few employers now demand "Oxbridge". Strong students will often take a Masters and if they do well on their UG course will have the opportunity to switch to Oxbridge at that point. Eventual success will probably rely as much on study skills, willingness to engage, time management, ability to work with others, initiative and ability to self-start, etc. All things DC picked up at school, and which meant that they were ready for University when they finally got there.