I have watched American Idol from year one. All the people left can have successful careers at this point. Winning the competition is not really necessary. Having this many people see you perform makes them winners. Plus some people don't really want to win. I think those that skew towards the rock genre might have an issue trying to play it down if they actually won it.
And about last night, I think that Jessica Sanchez has amazing talent, but something bothers me about her. I just don't like her that much.