Plant Science is an umbrella term under which many categories can exist. It is obviously a very broad title, an encompassing term rather than a narrow one.

But, I'm not at all sure what your point is.

I think Plant Science is more generally easier to sell as a class. I am sure there are new students who have never heard of Botany. Plant Science is just less scary than Botany. Sorry state of how the sciences have to be made more palatable to none scientific students.

I don't think it's easier to sell; I think it has a different meaning. Plant science includes horticulture, agriculture, agronomy, etc. In my experience, botany is typically found at a liberal arts college (that's where my degree in botany comes from) and plant science at universities that have broader offerings.

I also suppose that the source of instructors may be different. Botany courses requiring instructors with degrees in Botany and Plant Science courses could be degreed in hort., agriculture, etc. as mentioned above. I took my courses in botany at a CA University but my degrees are all in Art. Not too many botany courses offered at art school! lol But then, not a football team either.