Academic jobs are a nightmare from the HR perspective. While the posting might be on the jobs portal, the files themselves initially go to the hiring department which comes up with a long and then medium list that they then do some preliminary screening before ending up with a short list for on-site interviews. This can take several months.
The search committee then comes up with a ranked list with some candidates "above the line" and some "below the line" that the department votes on. This list -- which may have one, two, or three people that the department thinks are hireable (or in some cases, none, if the search fails). This list then goes to the provost, equal opportunity, and numerous other sundry university committees before getting approved (or not) and sent back down the line. This can take several more months.
So we are now 4-6 (or 6-8) months into the search. The search can have several results:
- A single finalist who is contacted. Maybe they
dawdle for a couple of weeks in giving a reply. If they decide not
to take the job, then the search is failed. The department may or
may not be authorized to search again next year and if they are, the
search remains open.
- Two finalists. The first accepts (or not). If the first doesn't, the second is given a chance. If both decline, then it's a failed
- No finalists. Failed search and the slot goes back to the provost's office. It may or may not be returned to the department.
- The provost hates all of the finalists and either cancels the slot or forces the department to re-run the search.
In other words, there are many reasons why a job posting might still remain open even one or two years after the initial posting. Departments are hesitant to finally close files unless they are absolutely positive that they are never, ever getting that slot back again -- or that the person who accepted the offer really is going to show up on August 1st.