I’ve heard of this happening elsewhere as well (including a school that I worked at that changed their name at least a decade ago). Maybe the use of “botanist” has become less formal and so is falling out favor as a professional degree?
On the other hand, “Zoology” degrees/program and the use of the term “zoologist” are also falling out of favor as well.
Related but different note that there’s this thread from last year which covers some similar ground to this:
https://forum.inaturalist.org/t/the-rise-of-labeling-ourselves-birders-herpers-and-beyond/62751