To reiterate what I said before, as do resignations/retirements/deaths, particularly in non-STEM courses. One should assume that if an instructor is not there next year, the course will not be offered. Many of these courses were developed by that specific instructor based upon his/her own interests, which may not be shared by other faculty members.
Several years ago, when European History was still officially an AP course, the instructor, who had taught the class since QE2 came to the throne (slight exaggeration, but not by much), retired. As a result, the course was dropped because nobody else wanted to teach it. It was many years before it was added back into the Course of Study. More recently, Chris Gurry, for whom Gurry Rink is named, taught a very popular International Relations class that was always in high demand. Fortunately, I was able to take this course as an upper, because he retired at the end of that year, and the course was dropped.
On the flip side, I see some new courses that have been added, and I think, “Damn, I wish they offered that when I was there.”