Why is Sanjaya Malakar, widely considered the worst American idol finalist in history, continue to get voted through? How can the worst singer continue to be loved by Americans?. I can think of a few economic explanations.
1) Rational Ignorance - This is actually an extension of rational ignorance. It's not exactly voters are rationally ignorant (they don't know), its more that the aggregate of voters don't care one way or the other who wins. Most of the viewers either watch the show without voting or vote once or twice for a good contestant. But Sanjaya has a whole army of people dedicated to voting for him 100's of times each.
I give you this summary from Howard Stern:
Howard started by saying he stayed up last night to vote for Sanjaya after “American Idol,” while Robin noted she called in for him as well, while Artie admitted he went to bed to take a nap, just to be ready to vote, but ended up sleeping until 4:30 a.m. and therefore wasn’t able to help the cause. Artie did point out, though, how angry he thought Beth was about Howard’s Sanjaya campaign when she spoke about it as a co-host on “The View” yesterday. Howard went on to say he started voting for Sanjaya at 9:05 p.m. and that he got through only twice. However, Robin added she was able to vote “30 or 40 times” when she called. Robin also commented she felt like Simon Cowell was speaking directly to Howard and his fans last night when he told Sanjaya that nothing he said about his performance mattered if “they” wanted him to win.
There are even computer programs set up to dial his number 100's, even 1000's of times a night.
2) Marginal Benefit/Marginal Cost - Some of the less crazy people may nevertheless be phoning up to vote for Sanjaya because the marginal benefit of seeing him look like below outweighs the cost of losing one of the better singers in the competition (who are, let's admit, not exactly the best this year). In other words, watching Sanjaya is fun and makes for interesting water cooler talk.