Following the final Idol ep this season, as in all seasons past, all 12 Finalists will embark upon a tightly-controlled 52-stop tour of the country, and any studio time any performer has can and will be within the scope of the performer's contract with the show. While Spike Seacrest says that the person voted out "goes home," that's not really what happens. They might go home for a visit, but they are still under contract. They'll do the tour, and then - THEN - they are free to pursue contracts and record deals if they haven't already gotten them from the show itself.
Michael
Whether you like their programming or not, Fox is running circles around the competition in terms of marketing.
For instance, ever notice how many stars of other Fox shows just happen to be in the audience to chat with Seacrest?
I even suspect that the guest judges (Manilow, Summer, etc.) have record deals tied to Fox, and thus get more publicity for upcoming records and tours.
Even their drama shows always point out that "this episode contained music from XXX" and show a copy of the CD.