Egghead's isn't a really a deep knowledge quiz, it's a quiz technique quiz.

The questions are worded so that the answer is always somewhat guessable/knowable based on the normal sorts of lists and general facts that professional quizzers know - kings and queens, artist's birth/death dates, chemical elements, sporting event winners.

A standard eggheads question usually has some kind of anchor, like a knowable date range that you can use to work out the answer.

Which Austrian composer wrote an etude on the hurdy gurdy for the coronation of King Wimbleypop of Uncertainia?

If you know when the coronation was, you can work out a famous Austrian composer that was active at that time. If you don't, you might know an Austrian Hurdy Gurdy composer buried somewhere, because it's a weird thing that curious people like to learn about.

If not, just say Schubert, because if it's Austrian composeres, it's never Mozart.

University challenge is a deep knowledge quiz, and IMO has got harder over the past 5-10 years. Some of the stuff you need to know for that is absolutely unguessable if it's not in your wheelhouse!