I dont think he was being serious, i think he was joking
Cambridge is a gd uni, as is oxford. But remember that even though these unis rank high each year a lot of it comes from reputation.
If u go to either average joe bloggs will go 'oooooo'. for ages they were the only unis, so it makes sense that they were accociated with excellence. But does it push the buttons within your academic field?
Ive done work experience with Imperial and my mother used to work there. the general feeling from academic staff is that they dont see oxbridge graduates as the cream. For physics they prefer Durham students, for chem and engineering they prefer Uni of London.
Getting into uni is a bit like the GCSE's. They seem dead important at the time, but essentially the degree you get at the end is more important.
Remember if u dont get into ur uni, its likely only to be judged by an interview after AS. Therefore they cant get the best everytime, or they wouldnt get drop-outs. Plus the best of manchester, liverpool, durham etc is going to better than minimum 70% of the students at oxbridge. Its not the elite! Its the same in grammars. Although on average they do better, they will have weaker students, where students who failed to get in our better.
Perhaps its time to get UK wide exams, to see who are the best. At the end of the day u cant compare an Oxford 1st to a York 1st, as they are completely different.
Good luck in wateva ur uni, i wish u success!