But there are also collective reasons to teach effectively. This piece in the IHE provides evidence for what I suspect most university faculty already notice: Students' academic interests are malleable, and the discipline they choose to study often turns on the instructor who firsts introduces them to it:
Undergraduates are significantly more likely to major in a field if they have an inspiring and caring faculty member in their introduction to the field. And they are equally likely to write off a field based on a single negative experience with a professor.
What [the researchers] found challenges the views of many experts that choice of major is “fixed” by such factors as a desire for a lucrative career. And their findings also suggest that those policy makers who want to attract more students to science and technology fields need to focus on teaching quality in those fields, not just financial benefits.
Overwhelmingly, the authors write, students’ "taste formation" in choice of major is due to faculty members, although the influence can go either way. "Faculty determine students' taste for academic fields by acting as gatekeepers, either by welcoming them into an area of knowledge, encouraging and inspiring them to explore it, or by raising the costs of entry so high so as to effectively prohibit continuing in it," Takacs and Chambliss write. "Faculty can positively or negatively influence student taste for a field -- some compelling teachers can get students engaged in fields that they previously disliked, while other, more uncharismatic faculty can alienate students from entire bodies of knowledge, sometimes permanently."
...interviews -- up to four years after graduation -- found that students remembered the professors who inspired them and those who annoyed them, and attributed their decisions on majors to those faculty members.
While part of the students’ judgments of their professors in the new study was based on the quality of lectures and presentations, far more was about the extent to which professors were engaged with students, took steps to get to know their students, were personally accessible, and so forth.
I suspect that this observation — that students often "major in the professor" — is particularly salient in philosophy. Students rarely come to college with any knowledge of philosophy and are usually introduced to it via a required intro course. In that situation, first impressions are likely to have more impact than they would in, say, history, where students already have some exposure to the discipline from secondary school.
There's been a lot of teeth gnashing in recent years about the humanities, about attracting students (particularly women and minorities) to the philosophy major, about making our work more visible to (and appreciated by) the wider public. Perhaps a possible solution has been under our noses all along: have enthusiastic, competent, engaged teachers, particularly at the introductory level.