Some dancers become teachers when they move to a town/city where are no swing dance happening. Then they start teaching, because they want to have someone to dance with.
And there are some dancers who become teachers because they want to share what they know or they are able to teach, because of their experience/skills.
If I had to bet on which one would care about their students, I would bet on the first one. Because you can teach and share what you know and inspire your students. Or you can do everything so your students dance with you because you need friends to dance with.