Simon (and the producers) have at least known that Taylor "sang himself into the semifinals" several weeks ago, probably with "Levon," the song Taylor sang for his first performance for the voting public during the Top 24 contest. That night, Simon said he thought Taylor should make the Top 10 and that Taylor was the contestant he was getting the most positive feedback from the public about. I would further speculate that the producers have known for a while that Taylor is going to win this thing and they have already commissioned the writing of his song for the finale. [Gawd I hope it's decent.]
Lets be real folks, Taylor is the perfect contestant: He's so confident and positive about his music, original as hell and funny to boot. And Taylor not only far surpasses the other contestants in vocal and performing ability, but he is better than a number of current superstars in the industry. And Taylor is the first AI contestant to not only be compared on an equal footing with the stars who originally performed his AI cover songs, but in some cases, rated BETTER than the original. For example, the Washington Post said his version of "Taking It to the Streets" was better than Michael McDonald's.
I think the producers and judges adore Taylor as much as we do, but they have wanted to maintain the ILLUSION of a contest, hence not giving Taylor the pimp spot as often, changing his songs at the last minute and unrealistically promoting Kellie and Katherine in the earlier weeks. Also, there have been some out-of-character, blase comments from Randy about a couple terrific Taylor performances. And Simon, well, he's just being Simon with the anti-dancing schitck.
[Side note: Did anyone notice that Simon referred to Taylor as "young man" last night? Such a contrast to Simon's past drunk- and sober- father references to Taylor. I guess Simon and the producers are ready to secure Taylor's run to the finish.]