Similar thing happened to me.
The "corporate" thinking behind continuing the search is that there is so much talent out there with the nations unemployment rate nearing 10% there MUST be someone better.
It is kinda like having a wife who is a 9/10 and feeling bad for yourself since you didnt marry a 10/10.
Like I said a similar thing happend to me, they said they would have a decision made by the end of the week but hopefully as soon as tomorrow. I also had to contact the potential employer. I think it is because the human resource departments dont really care about the people they interview. Almost like they think they are better than you. They dont take into consideration that this is your life