Let's say you had an on-campus interview 4 weeks ago, candidate 2 of 3. Let's say you have absolutely no reason to believe you weren't a perfectly acceptable candidate (even if not the best) and that follow-up emails from the faculty answered all your questions warmly and gave you reassurance that your interview was received favourably.
Suppose you then have evidence that the other two candidates have been offered the job, and both have turned it down; the last one did so over a week ago.
What are some possible reasons why you would not yet have received any word about an offer? Tied up in the dean's office again? Funds for the TT line withdrawn? Department told they could only have the TT line if they got one of their first 2 choices?
It is very difficult to believe they'd skip over their 3rd choice and dip back into the applicant pool after being as positive as they were during the interview process. But as an academic, one naturally has a deep enough reservoir of self-doubt to accept that this might be the case after all.