It's a gameshow. You win by being in the last two people and getting more questions right. So, you need to be better than at least one person and then eliminate other competitors. Being "The Strongest Link" just makes you a target for everybody who suspects they can't beat you in that final head-to-head round.
So the game can resolve to two devious but not-so-bright people who've schemed their way to the final two, and then one of them gets lucky with the topics.
If you want to watch something where people are just ludicrously good at general knowledge try "Only Connect" (even the title of the show is a relatively lesser known reference) but note they don't win prizes - why would they, they enjoy quizzes, they're not here for the money anyway.
So the game can resolve to two devious but not-so-bright people who've schemed their way to the final two, and then one of them gets lucky with the topics.
If you want to watch something where people are just ludicrously good at general knowledge try "Only Connect" (even the title of the show is a relatively lesser known reference) but note they don't win prizes - why would they, they enjoy quizzes, they're not here for the money anyway.