The judges are not looking for the same things that you or I would be, say as musicians auditioning a singer. For them, and for Simon Cowell in particular, the ideal winner will make the programme format owners lots of money by:[list]
[*]Selling records on the back of their looks, personality etc;
[*]Not questioning the contract they have to sign;
[*]Recording formulaic songs fed to them by the organisers' writing team (and not pester Simon with their own compositions, no matter how good); and
[*]Generally doing as they are told.
[/list]
In short, they are after a product they can sell, and a publishing rights revenue stream. If the contestant can more-or-less sing, so much the better!
When I criticise contestants for going off key, Mrs Axe always claims that I am not qualified to do so because I'm not performing in front of millions on national TV. I always reply that I get paid for my performances in less prestigious venues, and as a jobbing musician for over 20 years I am perfectly qualified to assess whether or not a singer makes the grade!