Without being mean, it's very simple at the end of the day. If you want to succeed in such a big event you have to be VERY professional. More than on a small stage in some club, more than in a talent show where everything is edited and scripted, more than on a show where you can lip-sing.
you need to know:
- when to sing and where to start singing
- how to get your pitches
- how to deliver in the right moment what you have trained.
She obviously didn't. That means - she's not professional enough for this show. She might be professional enough for other shows.
The reason for it is not important anymore. Every singer brings a story with him or her (some stories are known, some are leaked, some remain untold, some are visible, some aren't) and as difficult as they may be for everyone, these stories can not be weighted against each other, but more importantly they don't play any role here. The question is - can you deliver in the right moment that counts? The answer was given tonight.