Look, no one is suggesting all judges are going to recognise all longlisted novels. Of course they wouldn’t.
But your suggestion up the thread that judges given manuscripts without author names so that they judge blind, purely on ‘good writing’, is just not workable.
The prominent authors on the shortlist, if not immediately recognisable to a reading judge because of their style/subject matter, are going to be reviewed, advertised, discussed on arts programmes, piled up prominently in bookstores, and their authors will be appearing at literary festivals etc etc. A big debut likewise. If you are a judge, you will inevitably be able to identify some novels, whether because you know the author’s work already, or because you knew Colm Toibin was writing a sequel to Brooklyn, or you saw a review in the Guardian of a debut novel about an Australian who falls in love with the headmaster’s wife at an English boarding school, and lo and behold, your unnamed manuscript is about an Australian falling in love with a headmaster’s wife etc.
There’s no way of judging blind.