Well, had Sanjaya actually gone all the way to win Idol, I doubt that his win would all of a sudden mean that the show will never return. Idol is two things: a pop culture phenomenon that the teenyboppers and soccer moms trying to be as hip as their kids will always be sucked into viewing, and two, it's a massive advertising machine. If anything, the results would've just questioned the quality of the competition, at least for this season.
Like others on the board, I don't follow American Idol. It's plastic, even for L.A. standards...methinks.